HHH-17646 Optimize away real table group rendering if possible

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/DB2LegacySqlAstTranslator.java

@@ -76,7 +76,7 @@ public class DB2LegacySqlAstTranslator<T extends JdbcOperation> extends Abstract
 	}
 
 	@Override
-	protected void renderTableReferenceJoins(TableGroup tableGroup) {
+	protected void renderTableReferenceJoins(TableGroup tableGroup, int swappedJoinIndex, boolean forceLeftJoin) {
 		// When we are in a recursive CTE, we can't render joins on DB2...
 		// See https://modern-sql.com/feature/with-recursive/db2/error-345-state-42836
 		if ( isInRecursiveQueryPart() ) {
@@ -103,7 +103,7 @@ public class DB2LegacySqlAstTranslator<T extends JdbcOperation> extends Abstract
 			}
 		}
 		else {
-			super.renderTableReferenceJoins( tableGroup );
+			super.renderTableReferenceJoins( tableGroup, swappedJoinIndex, forceLeftJoin );
 		}
 	}
 

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/H2LegacySqlAstTranslator.java

@@ -340,13 +340,9 @@ public class H2LegacySqlAstTranslator<T extends JdbcOperation> extends AbstractS
 		final TableReference tableRef = tableGroup.getPrimaryTableReference();
 		// The H2 parser can't handle a sub-query as first element in a nested join
 		// i.e. `join ( (select ...) alias join ... )`, so we have to introduce a dummy table reference
-		if ( tableRef instanceof QueryPartTableReference || tableRef.getTableId().startsWith( "(select" ) ) {
+		if ( getSqlBuffer().charAt( getSqlBuffer().length() - 1 ) == '('
-			final boolean realTableGroup = tableGroup.isRealTableGroup()
+				&& ( tableRef instanceof QueryPartTableReference || tableRef.getTableId().startsWith( "(select" ) ) ) {
-					&& ( CollectionHelper.isNotEmpty( tableGroup.getTableReferenceJoins() )
+			appendSql( "dual cross join " );
-					|| hasNestedTableGroupsToRender( tableGroup.getNestedTableGroupJoins() ) );
-			if ( realTableGroup ) {
-				appendSql( "dual cross join " );
-			}
 		}
 		return super.renderPrimaryTableReference( tableGroup, lockMode );
 	}

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/HSQLLegacySqlAstTranslator.java

@@ -12,20 +12,14 @@ import java.util.function.Consumer;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.metamodel.mapping.JdbcMappingContainer;
 import org.hibernate.query.IllegalQueryOperationException;
-import org.hibernate.query.sqm.BinaryArithmeticOperator;
 import org.hibernate.query.sqm.ComparisonOperator;
 import org.hibernate.sql.ast.Clause;
 import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.spi.AbstractSqlAstTranslator;
 import org.hibernate.sql.ast.spi.SqlSelection;
-import org.hibernate.sql.ast.tree.MutationStatement;
 import org.hibernate.sql.ast.tree.Statement;
-import org.hibernate.sql.ast.tree.cte.CteStatement;
-import org.hibernate.sql.ast.tree.delete.DeleteStatement;
-import org.hibernate.sql.ast.tree.expression.BinaryArithmeticExpression;
 import org.hibernate.sql.ast.tree.expression.CaseSearchedExpression;
 import org.hibernate.sql.ast.tree.expression.CaseSimpleExpression;
-import org.hibernate.sql.ast.tree.expression.ColumnReference;
 import org.hibernate.sql.ast.tree.expression.Expression;
 import org.hibernate.sql.ast.tree.expression.Literal;
 import org.hibernate.sql.ast.tree.expression.SqlTuple;
@@ -147,8 +141,7 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 	protected void visitAnsiCaseSearchedExpression(
 			CaseSearchedExpression expression,
 			Consumer<Expression> resultRenderer) {
-		if ( getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT && areAllResultsParameters( expression )
+		if ( areAllResultsPlainParametersOrStringLiterals( expression ) ) {
-				|| areAllResultsPlainParametersOrLiterals( expression ) ) {
 			final List<CaseSearchedExpression.WhenFragment> whenFragments = expression.getWhenFragments();
 			final Expression firstResult = whenFragments.get( 0 ).getResult();
 			super.visitAnsiCaseSearchedExpression(
@@ -172,8 +165,7 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 	protected void visitAnsiCaseSimpleExpression(
 			CaseSimpleExpression expression,
 			Consumer<Expression> resultRenderer) {
-		if ( getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT && areAllResultsParameters( expression )
+		if ( areAllResultsPlainParametersOrStringLiterals( expression ) ) {
-				|| areAllResultsPlainParametersOrLiterals( expression ) ) {
 			final List<CaseSimpleExpression.WhenFragment> whenFragments = expression.getWhenFragments();
 			final Expression firstResult = whenFragments.get( 0 ).getResult();
 			super.visitAnsiCaseSimpleExpression(
@@ -193,11 +185,11 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 		}
 	}
 
-	protected boolean areAllResultsPlainParametersOrLiterals(CaseSearchedExpression caseSearchedExpression) {
+	protected boolean areAllResultsPlainParametersOrStringLiterals(CaseSearchedExpression caseSearchedExpression) {
 		final List<CaseSearchedExpression.WhenFragment> whenFragments = caseSearchedExpression.getWhenFragments();
 		final Expression firstResult = whenFragments.get( 0 ).getResult();
 		if ( isParameter( firstResult ) && getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT
-				|| isLiteral( firstResult ) ) {
+				|| isStringLiteral( firstResult ) ) {
 			for ( int i = 1; i < whenFragments.size(); i++ ) {
 				final Expression result = whenFragments.get( i ).getResult();
 				if ( isParameter( result ) ) {
@@ -205,7 +197,7 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 						return false;
 					}
 				}
-				else if ( !isLiteral( result ) ) {
+				else if ( !isStringLiteral( result ) ) {
 					return false;
 				}
 			}
@@ -214,11 +206,11 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 		return false;
 	}
 
-	protected boolean areAllResultsPlainParametersOrLiterals(CaseSimpleExpression caseSimpleExpression) {
+	protected boolean areAllResultsPlainParametersOrStringLiterals(CaseSimpleExpression caseSimpleExpression) {
 		final List<CaseSimpleExpression.WhenFragment> whenFragments = caseSimpleExpression.getWhenFragments();
 		final Expression firstResult = whenFragments.get( 0 ).getResult();
 		if ( isParameter( firstResult ) && getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT
-				|| isLiteral( firstResult ) ) {
+				|| isStringLiteral( firstResult ) ) {
 			for ( int i = 1; i < whenFragments.size(); i++ ) {
 				final Expression result = whenFragments.get( i ).getResult();
 				if ( isParameter( result ) ) {
@@ -226,7 +218,7 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 						return false;
 					}
 				}
-				else if ( !isLiteral( result ) ) {
+				else if ( !isStringLiteral( result ) ) {
 					return false;
 				}
 			}
@@ -235,6 +227,13 @@ public class HSQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstrac
 		return false;
 	}
 
+	private boolean isStringLiteral( Expression expression ) {
+		if ( expression instanceof Literal ) {
+			return ( (Literal) expression ).getJdbcMapping().getJdbcType().isStringLike();
+		}
+		return false;
+	}
+
 	@Override
 	public boolean supportsFilterClause() {
 		return true;

hibernate-core/src/main/java/org/hibernate/dialect/DB2SqlAstTranslator.java

@@ -75,7 +75,7 @@ public class DB2SqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAst
 	}
 
 	@Override
-	protected void renderTableReferenceJoins(TableGroup tableGroup) {
+	protected void renderTableReferenceJoins(TableGroup tableGroup, int swappedJoinIndex, boolean forceLeftJoin) {
 		// When we are in a recursive CTE, we can't render joins on DB2...
 		// See https://modern-sql.com/feature/with-recursive/db2/error-345-state-42836
 		if ( isInRecursiveQueryPart() ) {
@@ -102,7 +102,7 @@ public class DB2SqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAst
 			}
 		}
 		else {
-			super.renderTableReferenceJoins( tableGroup );
+			super.renderTableReferenceJoins( tableGroup, swappedJoinIndex, forceLeftJoin );
 		}
 	}
 

hibernate-core/src/main/java/org/hibernate/dialect/H2SqlAstTranslator.java

@@ -314,13 +314,9 @@ public class H2SqlAstTranslator<T extends JdbcOperation> extends SqlAstTranslato
 		final TableReference tableRef = tableGroup.getPrimaryTableReference();
 		// The H2 parser can't handle a sub-query as first element in a nested join
 		// i.e. `join ( (select ...) alias join ... )`, so we have to introduce a dummy table reference
-		if ( tableRef instanceof QueryPartTableReference || tableRef.getTableId().startsWith( "(select" ) ) {
+		if ( getSqlBuffer().charAt( getSqlBuffer().length() - 1 ) == '('
-			final boolean realTableGroup = tableGroup.isRealTableGroup()
+				&& ( tableRef instanceof QueryPartTableReference || tableRef.getTableId().startsWith( "(select" ) ) ) {
-					&& ( isNotEmpty( tableGroup.getTableReferenceJoins() )
+			appendSql( "dual cross join " );
-					|| hasNestedTableGroupsToRender( tableGroup.getNestedTableGroupJoins() ) );
-			if ( realTableGroup ) {
-				appendSql( "dual cross join " );
-			}
 		}
 		return super.renderPrimaryTableReference( tableGroup, lockMode );
 	}

hibernate-core/src/main/java/org/hibernate/dialect/HSQLSqlAstTranslator.java

@@ -12,14 +12,12 @@ import java.util.function.Consumer;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.metamodel.mapping.JdbcMappingContainer;
 import org.hibernate.query.IllegalQueryOperationException;
-import org.hibernate.query.sqm.BinaryArithmeticOperator;
 import org.hibernate.query.sqm.ComparisonOperator;
 import org.hibernate.sql.ast.Clause;
 import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.spi.AbstractSqlAstTranslator;
 import org.hibernate.sql.ast.spi.SqlSelection;
 import org.hibernate.sql.ast.tree.Statement;
-import org.hibernate.sql.ast.tree.expression.BinaryArithmeticExpression;
 import org.hibernate.sql.ast.tree.expression.CaseSearchedExpression;
 import org.hibernate.sql.ast.tree.expression.CaseSimpleExpression;
 import org.hibernate.sql.ast.tree.expression.Expression;
@@ -152,8 +150,7 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 	protected void visitAnsiCaseSearchedExpression(
 			CaseSearchedExpression expression,
 			Consumer<Expression> resultRenderer) {
-		if ( getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT && areAllResultsParameters( expression )
+		if ( areAllResultsPlainParametersOrStringLiterals( expression ) ) {
-				|| areAllResultsPlainParametersOrLiterals( expression ) ) {
 			final List<CaseSearchedExpression.WhenFragment> whenFragments = expression.getWhenFragments();
 			final Expression firstResult = whenFragments.get( 0 ).getResult();
 			super.visitAnsiCaseSearchedExpression(
@@ -177,8 +174,7 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 	protected void visitAnsiCaseSimpleExpression(
 			CaseSimpleExpression expression,
 			Consumer<Expression> resultRenderer) {
-		if ( getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT && areAllResultsParameters( expression )
+		if ( areAllResultsPlainParametersOrStringLiterals( expression ) ) {
-				|| areAllResultsPlainParametersOrLiterals( expression ) ) {
 			final List<CaseSimpleExpression.WhenFragment> whenFragments = expression.getWhenFragments();
 			final Expression firstResult = whenFragments.get( 0 ).getResult();
 			super.visitAnsiCaseSimpleExpression(
@@ -198,11 +194,11 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 		}
 	}
 
-	protected boolean areAllResultsPlainParametersOrLiterals(CaseSearchedExpression caseSearchedExpression) {
+	protected boolean areAllResultsPlainParametersOrStringLiterals(CaseSearchedExpression caseSearchedExpression) {
 		final List<CaseSearchedExpression.WhenFragment> whenFragments = caseSearchedExpression.getWhenFragments();
 		final Expression firstResult = whenFragments.get( 0 ).getResult();
 		if ( isParameter( firstResult ) && getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT
-				|| isLiteral( firstResult ) ) {
+				|| isStringLiteral( firstResult ) ) {
 			for ( int i = 1; i < whenFragments.size(); i++ ) {
 				final Expression result = whenFragments.get( i ).getResult();
 				if ( isParameter( result ) ) {
@@ -210,7 +206,7 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 						return false;
 					}
 				}
-				else if ( !isLiteral( result ) ) {
+				else if ( !isStringLiteral( result ) ) {
 					return false;
 				}
 			}
@@ -219,11 +215,11 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 		return false;
 	}
 
-	protected boolean areAllResultsPlainParametersOrLiterals(CaseSimpleExpression caseSimpleExpression) {
+	protected boolean areAllResultsPlainParametersOrStringLiterals(CaseSimpleExpression caseSimpleExpression) {
 		final List<CaseSimpleExpression.WhenFragment> whenFragments = caseSimpleExpression.getWhenFragments();
 		final Expression firstResult = whenFragments.get( 0 ).getResult();
 		if ( isParameter( firstResult ) && getParameterRenderingMode() == SqlAstNodeRenderingMode.DEFAULT
-				|| isLiteral( firstResult ) ) {
+				|| isStringLiteral( firstResult ) ) {
 			for ( int i = 1; i < whenFragments.size(); i++ ) {
 				final Expression result = whenFragments.get( i ).getResult();
 				if ( isParameter( result ) ) {
@@ -231,7 +227,7 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 						return false;
 					}
 				}
-				else if ( !isLiteral( result ) ) {
+				else if ( !isStringLiteral( result ) ) {
 					return false;
 				}
 			}
@@ -240,6 +236,13 @@ public class HSQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAs
 		return false;
 	}
 
+	private boolean isStringLiteral( Expression expression ) {
+		if ( expression instanceof Literal ) {
+			return ( (Literal) expression ).getJdbcMapping().getJdbcType().isStringLike();
+		}
+		return false;
+	}
+
 	@Override
 	public boolean supportsFilterClause() {
 		return true;

hibernate-core/src/main/java/org/hibernate/metamodel/internal/AbstractCompositeIdentifierMapping.java

@@ -48,6 +48,8 @@ import org.hibernate.sql.results.graph.embeddable.EmbeddableValuedFetchable;
 import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableFetchImpl;
 import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableResultImpl;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Base implementation for composite identifier mappings
  *
@@ -129,9 +131,9 @@ public abstract class AbstractCompositeIdentifierMapping
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
@@ -154,11 +156,11 @@ public abstract class AbstractCompositeIdentifierMapping
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		return new StandardVirtualTableGroup( navigablePath, this, lhs, fetched );
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/EntityMappingType.java

@@ -292,6 +292,14 @@ public interface EntityMappingType
 	 */
 	EntityIdentifierMapping getIdentifierMapping();
 
+	/**
+	 * Mapping details for the entity's identifier.  This is shared across all
+	 * entity mappings within an inheritance hierarchy.
+	 */
+	default EntityIdentifierMapping getIdentifierMappingForJoin() {
+		return getIdentifierMapping();
+	}
+
 	/**
 	 * Mapping details for the entity's discriminator.  This is shared across all
 	 * entity mappings within an inheritance hierarchy.

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/CaseStatementDiscriminatorMappingImpl.java

@@ -6,7 +6,9 @@
  */
 package org.hibernate.metamodel.mapping.internal;
 
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
+import java.util.List;
 
 import org.hibernate.engine.FetchTiming;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
@@ -255,6 +257,24 @@ public class CaseStatementDiscriminatorMappingImpl extends AbstractDiscriminator
 			this.entityTableGroup = entityTableGroup;
 		}
 
+		public List<TableReference> getUsedTableReferences() {
+			final ArrayList<TableReference> usedTableReferences = new ArrayList<>( tableDiscriminatorDetailsMap.size() );
+			tableDiscriminatorDetailsMap.forEach(
+					(tableName, tableDiscriminatorDetails) -> {
+						final TableReference tableReference = entityTableGroup.getTableReference(
+								entityTableGroup.getNavigablePath(),
+								tableName,
+								false
+						);
+
+						if ( tableReference != null ) {
+							usedTableReferences.add( tableReference );
+						}
+					}
+			);
+			return usedTableReferences;
+		}
+
 		@Override
 		public void renderToSql(
 				SqlAppender sqlAppender,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/DiscriminatedAssociationAttributeMapping.java

@@ -52,6 +52,8 @@ import org.hibernate.type.AnyType;
 import org.hibernate.type.descriptor.java.JavaType;
 import org.hibernate.type.descriptor.java.MutabilityPlan;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * Singular, any-valued attribute
  *
@@ -487,9 +489,9 @@ public class DiscriminatedAssociationAttributeMapping
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
@@ -512,11 +514,11 @@ public class DiscriminatedAssociationAttributeMapping
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		return new StandardVirtualTableGroup( navigablePath, this, lhs, fetched );
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/DiscriminatedCollectionPart.java

@@ -45,6 +45,10 @@ import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.type.AnyType;
 import org.hibernate.type.descriptor.java.JavaType;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static java.util.Objects.requireNonNullElse;
+
 /**
  * @author Steve Ebersole
  */
@@ -343,19 +347,13 @@ public class DiscriminatedCollectionPart implements DiscriminatedAssociationMode
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
-		final SqlAstJoinType joinType;
+		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
-		if ( requestedJoinType == null ) {
-			joinType = SqlAstJoinType.INNER;
-		}
-		else {
-			joinType = requestedJoinType;
-		}
 		final TableGroup tableGroup = createRootTableGroupJoin(
 				navigablePath,
 				lhs,
@@ -374,11 +372,11 @@ public class DiscriminatedCollectionPart implements DiscriminatedAssociationMode
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		return new StandardVirtualTableGroup( navigablePath, this, lhs, fetched );
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EmbeddedAttributeMapping.java

@@ -53,6 +53,10 @@ import org.hibernate.sql.results.graph.embeddable.internal.AggregateEmbeddableRe
 import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableFetchImpl;
 import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableResultImpl;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static java.util.Objects.requireNonNullElse;
+
 /**
  * @author Steve Ebersole
  */
@@ -318,13 +322,13 @@ public class EmbeddedAttributeMapping
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
-		final SqlAstJoinType joinType = requestedJoinType == null ? SqlAstJoinType.INNER : requestedJoinType;
+		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
 		final TableGroup tableGroup = createRootTableGroupJoin(
 				navigablePath,
 				lhs,
@@ -343,11 +347,11 @@ public class EmbeddedAttributeMapping
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		return new StandardVirtualTableGroup( navigablePath, this, lhs, fetched );
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/EmbeddedCollectionPart.java

@@ -13,7 +13,6 @@ import java.util.function.Consumer;
 
 import org.hibernate.engine.FetchStyle;
 import org.hibernate.engine.FetchTiming;
-import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.metamodel.mapping.CollectionPart;
 import org.hibernate.metamodel.mapping.EmbeddableMappingType;
 import org.hibernate.metamodel.mapping.EntityMappingType;
@@ -21,7 +20,6 @@ import org.hibernate.metamodel.mapping.JdbcMapping;
 import org.hibernate.metamodel.mapping.MappingType;
 import org.hibernate.metamodel.mapping.ModelPart;
 import org.hibernate.metamodel.mapping.PluralAttributeMapping;
-import org.hibernate.metamodel.mapping.SelectableConsumer;
 import org.hibernate.metamodel.model.domain.NavigableRole;
 import org.hibernate.persister.collection.CollectionPersister;
 import org.hibernate.property.access.internal.PropertyAccessStrategyBasicImpl;
@@ -41,7 +39,6 @@ import org.hibernate.sql.ast.tree.from.PluralTableGroup;
 import org.hibernate.sql.ast.tree.from.StandardVirtualTableGroup;
 import org.hibernate.sql.ast.tree.from.TableGroup;
 import org.hibernate.sql.ast.tree.from.TableGroupJoin;
-import org.hibernate.sql.ast.tree.from.TableGroupProducer;
 import org.hibernate.sql.ast.tree.from.TableReference;
 import org.hibernate.sql.ast.tree.predicate.Predicate;
 import org.hibernate.sql.results.graph.DomainResult;
@@ -49,12 +46,15 @@ import org.hibernate.sql.results.graph.DomainResultCreationState;
 import org.hibernate.sql.results.graph.Fetch;
 import org.hibernate.sql.results.graph.FetchOptions;
 import org.hibernate.sql.results.graph.FetchParent;
-import org.hibernate.sql.results.graph.Fetchable;
 import org.hibernate.sql.results.graph.embeddable.EmbeddableValuedFetchable;
 import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableFetchImpl;
 import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableResultImpl;
 import org.hibernate.type.descriptor.java.JavaType;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static java.util.Objects.requireNonNullElse;
+
 /**
  * @author Steve Ebersole
  */
@@ -231,19 +231,13 @@ public class EmbeddedCollectionPart implements CollectionPart, EmbeddableValuedF
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
-		final SqlAstJoinType joinType;
+		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
-		if ( requestedJoinType == null ) {
-			joinType = SqlAstJoinType.INNER;
-		}
-		else {
-			joinType = requestedJoinType;
-		}
 		final TableGroup tableGroup = createRootTableGroupJoin(
 				navigablePath,
 				lhs,
@@ -262,11 +256,11 @@ public class EmbeddedCollectionPart implements CollectionPart, EmbeddableValuedF
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		assert lhs.getModelPart() instanceof PluralAttributeMapping;
 		return new StandardVirtualTableGroup( navigablePath, this, lhs, fetched );

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/ManyToManyCollectionPart.java

@@ -56,6 +56,8 @@ import org.hibernate.sql.ast.tree.from.TableReference;
 import org.hibernate.sql.ast.tree.predicate.Predicate;
 import org.hibernate.type.EntityType;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import static java.util.Objects.requireNonNullElse;
 import static org.hibernate.metamodel.mapping.internal.MappingModelCreationHelper.createInverseModelPart;
 import static org.hibernate.metamodel.mapping.internal.MappingModelCreationHelper.getPropertyOrder;
@@ -258,14 +260,13 @@ public class ManyToManyCollectionPart extends AbstractEntityCollectionPart imple
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
 		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
-
 		final LazyTableGroup lazyTableGroup = createRootTableGroupJoin(
 				navigablePath,
 				lhs,
@@ -302,11 +303,11 @@ public class ManyToManyCollectionPart extends AbstractEntityCollectionPart imple
 	public LazyTableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
 		final boolean canUseInnerJoin = joinType == SqlAstJoinType.INNER || lhs.canUseInnerJoins();
@@ -393,7 +394,8 @@ public class ManyToManyCollectionPart extends AbstractEntityCollectionPart imple
 				fkTargetModelPart = resolveNamedTargetPart( mapKeyPropertyName, entityMappingType, collectionDescriptor );
 			}
 			else {
-				fkTargetModelPart = getAssociatedEntityMappingType().getIdentifierMapping();
+				fkTargetModelPart = getAssociatedEntityMappingType().getIdentifierMappingForJoin();
+//				fkTargetModelPart = getAssociatedEntityMappingType().getIdentifierMapping();
 			}
 		}
 		else if ( StringHelper.isNotEmpty( bootCollectionDescriptor.getMappedByProperty() ) ) {
@@ -449,7 +451,8 @@ public class ManyToManyCollectionPart extends AbstractEntityCollectionPart imple
 		}
 		else {
 			// non-inverse @ManyToMany
-			fkTargetModelPart = getAssociatedEntityMappingType().getIdentifierMapping();
+			fkTargetModelPart = getAssociatedEntityMappingType().getIdentifierMappingForJoin();
+//			fkTargetModelPart = getAssociatedEntityMappingType().getIdentifierMapping();
 		}
 
 		if ( getNature() == Nature.ELEMENT ) {

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/MappingModelCreationHelper.java

@@ -116,6 +116,8 @@ import org.hibernate.type.descriptor.java.MutabilityPlan;
 import org.hibernate.type.descriptor.java.spi.JavaTypeRegistry;
 import org.hibernate.type.spi.TypeConfiguration;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import static org.hibernate.internal.util.NullnessUtil.castNonNull;
 import static org.hibernate.metamodel.mapping.MappingModelCreationLogging.MAPPING_MODEL_CREATION_MESSAGE_LOGGER;
 import static org.hibernate.sql.ast.spi.SqlExpressionResolver.createColumnReferenceKey;
@@ -775,7 +777,8 @@ public class MappingModelCreationHelper {
 		}
 
 		if ( isReferenceToPrimaryKey ) {
-			fkTargetPart = collectionDescriptor.getOwnerEntityPersister().getIdentifierMapping();
+			fkTargetPart = collectionDescriptor.getOwnerEntityPersister().getIdentifierMappingForJoin();
+//			fkTargetPart = collectionDescriptor.getOwnerEntityPersister().getIdentifierMapping();
 		}
 		else {
 			fkTargetPart = declaringType.findContainingEntityMapping().findSubPart( lhsPropertyName );
@@ -928,7 +931,8 @@ public class MappingModelCreationHelper {
 
 		final ModelPart fkTarget;
 		if ( bootValueMapping.isReferenceToPrimaryKey() ) {
-			fkTarget = referencedEntityDescriptor.getIdentifierMapping();
+			fkTarget = referencedEntityDescriptor.getIdentifierMappingForJoin();
+//			fkTarget = referencedEntityDescriptor.getIdentifierMapping();
 		}
 		else {
 			fkTarget = referencedEntityDescriptor.findByPath( bootValueMapping.getReferencedPropertyName() );
@@ -1677,9 +1681,9 @@ public class MappingModelCreationHelper {
 						public TableGroupJoin createTableGroupJoin(
 								NavigablePath navigablePath,
 								TableGroup lhs,
-								String explicitSourceAlias,
+								@Nullable String explicitSourceAlias,
-								SqlAliasBase explicitSqlAliasBase,
+								@Nullable SqlAliasBase explicitSqlAliasBase,
-								SqlAstJoinType sqlAstJoinType,
+								@Nullable SqlAstJoinType sqlAstJoinType,
 								boolean fetched,
 								boolean addsPredicate,
 								SqlAstCreationState creationState) {
@@ -1690,11 +1694,11 @@ public class MappingModelCreationHelper {
 						public TableGroup createRootTableGroupJoin(
 								NavigablePath navigablePath,
 								TableGroup lhs,
-								String explicitSourceAlias,
+								@Nullable String explicitSourceAlias,
-								SqlAliasBase explicitSqlAliasBase,
+								@Nullable SqlAliasBase explicitSqlAliasBase,
-								SqlAstJoinType sqlAstJoinType,
+								@Nullable SqlAstJoinType sqlAstJoinType,
 								boolean fetched,
-								Consumer<Predicate> predicateConsumer,
+								@Nullable Consumer<Predicate> predicateConsumer,
 								SqlAstCreationState creationState) {
 							return null;
 						}

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/OneToManyCollectionPart.java

@@ -31,6 +31,8 @@ import org.hibernate.sql.ast.tree.from.TableGroupJoin;
 import org.hibernate.sql.ast.tree.from.TableGroupJoinProducer;
 import org.hibernate.sql.ast.tree.predicate.Predicate;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import static java.util.Objects.requireNonNullElse;
 
 /**
@@ -154,9 +156,9 @@ public class OneToManyCollectionPart extends AbstractEntityCollectionPart implem
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
@@ -193,11 +195,11 @@ public class OneToManyCollectionPart extends AbstractEntityCollectionPart implem
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		return createTableGroupInternal(
 				true,

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/PluralAttributeMappingImpl.java

@@ -75,6 +75,8 @@ import org.hibernate.sql.results.graph.collection.internal.SelectEagerCollection
 
 import org.jboss.logging.Logger;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import static org.hibernate.boot.model.internal.SoftDeleteHelper.createNonSoftDeletedRestriction;
 import static org.hibernate.boot.model.internal.SoftDeleteHelper.resolveSoftDeleteMapping;
 
@@ -683,9 +685,9 @@ public class PluralAttributeMappingImpl
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
@@ -802,7 +804,7 @@ public class PluralAttributeMappingImpl
 		}
 	}
 
-	public SqlAstJoinType determineSqlJoinType(TableGroup lhs, SqlAstJoinType requestedJoinType, boolean fetched) {
+	public SqlAstJoinType determineSqlJoinType(TableGroup lhs, @Nullable SqlAstJoinType requestedJoinType, boolean fetched) {
 		if ( hasSoftDelete() ) {
 			return SqlAstJoinType.LEFT;
 		}
@@ -824,11 +826,11 @@ public class PluralAttributeMappingImpl
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		return createRootTableGroupJoin(
 				navigablePath,
@@ -861,8 +863,10 @@ public class PluralAttributeMappingImpl
 		if ( collectionDescriptor.isOneToMany() ) {
 			tableGroup = createOneToManyTableGroup(
 					lhs.canUseInnerJoins() && joinType == SqlAstJoinType.INNER,
+					joinType,
 					navigablePath,
 					fetched,
+					addsPredicate,
 					explicitSourceAlias,
 					sqlAliasBase,
 					creationState
@@ -896,8 +900,10 @@ public class PluralAttributeMappingImpl
 
 	private TableGroup createOneToManyTableGroup(
 			boolean canUseInnerJoins,
+			SqlAstJoinType joinType,
 			NavigablePath navigablePath,
 			boolean fetched,
+			boolean addsPredicate,
 			String sourceAlias,
 			SqlAliasBase explicitSqlAliasBase,
 			SqlAstCreationState creationState) {
@@ -920,6 +926,12 @@ public class PluralAttributeMappingImpl
 				elementTableGroup,
 				creationState.getCreationContext().getSessionFactory()
 		);
+		// For inner joins we never need join nesting
+		final boolean nestedJoin = joinType != SqlAstJoinType.INNER
+				// For outer joins we need nesting if there might be an on-condition that refers to the element table
+				&& ( addsPredicate
+				|| isAffectedByEnabledFilters( creationState.getLoadQueryInfluencers(), creationState.applyOnlyLoadByKeyFilters() )
+				|| collectionDescriptor.hasWhereRestrictions() );
 
 		if ( indexDescriptor instanceof TableGroupJoinProducer ) {
 			final TableGroupJoin tableGroupJoin = ( (TableGroupJoinProducer) indexDescriptor ).createTableGroupJoin(
@@ -932,7 +944,7 @@ public class PluralAttributeMappingImpl
 					false,
 					creationState
 			);
-			tableGroup.registerIndexTableGroup( tableGroupJoin );
+			tableGroup.registerIndexTableGroup( tableGroupJoin, nestedJoin );
 		}
 
 		return tableGroup;
@@ -1022,8 +1034,10 @@ public class PluralAttributeMappingImpl
 		if ( getCollectionDescriptor().isOneToMany() ) {
 			return createOneToManyTableGroup(
 					canUseInnerJoins,
+					SqlAstJoinType.INNER,
 					navigablePath,
 					false,
+					false,
 					explicitSourceAlias,
 					explicitSqlAliasBase,
 					creationState

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/ToOneAttributeMapping.java

@@ -66,6 +66,7 @@ import org.hibernate.persister.entity.JoinedSubclassEntityPersister;
 import org.hibernate.property.access.spi.PropertyAccess;
 import org.hibernate.proxy.HibernateProxy;
 import org.hibernate.proxy.LazyInitializer;
+import org.hibernate.query.sqm.sql.SqmToSqlAstConverter;
 import org.hibernate.spi.EntityIdentifierNavigablePath;
 import org.hibernate.spi.NavigablePath;
 import org.hibernate.spi.TreatedNavigablePath;
@@ -106,13 +107,14 @@ import org.hibernate.sql.results.graph.entity.internal.EntityFetchSelectImpl;
 import org.hibernate.sql.results.internal.NullValueAssembler;
 import org.hibernate.sql.results.internal.domain.CircularBiDirectionalFetchImpl;
 import org.hibernate.sql.results.internal.domain.CircularFetchImpl;
-import org.hibernate.type.ComponentType;
 import org.hibernate.type.CompositeType;
 import org.hibernate.type.EmbeddedComponentType;
 import org.hibernate.type.EntityType;
 import org.hibernate.type.Type;
 import org.hibernate.type.descriptor.java.JavaType;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import static org.hibernate.boot.model.internal.SoftDeleteHelper.createNonSoftDeletedRestriction;
 
 /**
@@ -855,6 +857,7 @@ public class ToOneAttributeMapping
 		// 		* the association does not force a join (`@NotFound`, nullable 1-1, ...)
 		// Otherwise we need to join to the associated entity table(s)
 		final boolean forceJoin = hasNotFoundAction()
+				|| entityMappingType.getSoftDeleteMapping() != null
 				|| ( cardinality == Cardinality.ONE_TO_ONE && isNullable() );
 		this.canUseParentTableGroup = ! forceJoin
 				&& sideNature == ForeignKeyDescriptor.Nature.KEY
@@ -1978,9 +1981,9 @@ public class ToOneAttributeMapping
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
@@ -2072,7 +2075,11 @@ public class ToOneAttributeMapping
 
 		final TableGroupJoin join = new TableGroupJoin(
 				navigablePath,
-				joinType,
+				// Avoid checking for nested joins in here again, since this is already done in createRootTableGroupJoin
+				// and simply rely on the canUseInnerJoins flag instead for override the join type to LEFT
+				requestedJoinType == null && !lazyTableGroup.canUseInnerJoins()
+						? SqlAstJoinType.LEFT
+						: joinType,
 				lazyTableGroup,
 				null
 		);
@@ -2144,7 +2151,7 @@ public class ToOneAttributeMapping
 	}
 
 	@Override
-	public SqlAstJoinType determineSqlJoinType(TableGroup lhs, SqlAstJoinType requestedJoinType, boolean fetched) {
+	public SqlAstJoinType determineSqlJoinType(TableGroup lhs, @Nullable SqlAstJoinType requestedJoinType, boolean fetched) {
 		if ( requestedJoinType != null ) {
 			return requestedJoinType;
 		}
@@ -2160,11 +2167,11 @@ public class ToOneAttributeMapping
 	public LazyTableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		final SqlAliasBase sqlAliasBase = SqlAliasBase.from(
 				explicitSqlAliasBase,
@@ -2174,18 +2181,16 @@ public class ToOneAttributeMapping
 		);
 
 		final SoftDeleteMapping softDeleteMapping = getAssociatedEntityMappingType().getSoftDeleteMapping();
-
 		final boolean canUseInnerJoin;
-		if ( ! lhs.canUseInnerJoins() ) {
+		final SqlAstJoinType currentlyProcessingJoinType = creationState instanceof SqmToSqlAstConverter
-			canUseInnerJoin = false;
+				? ( (SqmToSqlAstConverter) creationState ).getCurrentlyProcessingJoinType()
-		}
+				: null;
-		else if ( isNullable
+		if ( currentlyProcessingJoinType != null && currentlyProcessingJoinType != SqlAstJoinType.INNER ) {
-				|| hasNotFoundAction()
+			// Don't change the join type though, as that has implications for eager initialization of a LazyTableGroup
-				|| softDeleteMapping != null ) {
 			canUseInnerJoin = false;
 		}
 		else {
-			canUseInnerJoin = requestedJoinType == SqlAstJoinType.INNER;
+			canUseInnerJoin = determineSqlJoinType( lhs, requestedJoinType, fetched ) == SqlAstJoinType.INNER;
 		}
 
 		TableGroup realParentTableGroup = lhs;

hibernate-core/src/main/java/org/hibernate/persister/entity/AbstractEntityPersister.java

@@ -5814,6 +5814,7 @@ public abstract class AbstractEntityPersister
 	}
 
 	private ModelPart getIdentifierModelPart(String name, EntityMappingType treatTargetType) {
+		final EntityIdentifierMapping identifierMapping = getIdentifierMappingForJoin();
 		if ( identifierMapping instanceof NonAggregatedIdentifierMapping ) {
 			NonAggregatedIdentifierMapping mapping = (NonAggregatedIdentifierMapping) identifierMapping;
 			final ModelPart subPart = mapping.findSubPart( name, treatTargetType );

hibernate-core/src/main/java/org/hibernate/persister/entity/JoinedSubclassEntityPersister.java

@@ -1331,6 +1331,15 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 		}
 	}
 
+	@Override
+	public EntityIdentifierMapping getIdentifierMappingForJoin() {
+		// If the joined subclass has a physical discriminator and has subtypes
+		// we must use the root table identifier mapping for joining to allow table group elimination to work
+		return isPhysicalDiscriminator() && !getSubMappingTypes().isEmpty()
+				? getRootEntityDescriptor().getIdentifierMapping()
+				: super.getIdentifierMappingForJoin();
+	}
+
 	private boolean applyDiscriminatorPredicate(
 			TableReferenceJoin join,
 			NamedTableReference tableReference,
@@ -1341,9 +1350,11 @@ public class JoinedSubclassEntityPersister extends AbstractEntityPersister {
 			final String discriminatorPredicate = getPrunedDiscriminatorPredicate(
 					entityNameUses,
 					metamodel,
-					tableReference.getIdentificationVariable()
+					"t"
+//					tableReference.getIdentificationVariable()
 			);
-			join.applyPredicate( new SqlFragmentPredicate( discriminatorPredicate ) );
+			tableReference.setPrunedTableExpression( "(select * from " + getRootTableName() + " t where " + discriminatorPredicate + ")" );
+//			join.applyPredicate( new SqlFragmentPredicate( discriminatorPredicate ) );
 			return true;
 		}
 		return false;

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleEmbeddableValuedModelPart.java

@@ -63,6 +63,9 @@ import org.hibernate.sql.results.graph.embeddable.internal.EmbeddableResultImpl;
 import org.hibernate.type.descriptor.java.JavaType;
 
 import jakarta.persistence.metamodel.Attribute;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static java.util.Objects.requireNonNullElse;
 
 /**
  * @author Christian Beikov
@@ -341,13 +344,13 @@ public class AnonymousTupleEmbeddableValuedModelPart implements EmbeddableValued
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
-		final SqlAstJoinType joinType = requestedJoinType == null ? SqlAstJoinType.INNER : requestedJoinType;
+		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
 		final TableGroup tableGroup = createRootTableGroupJoin(
 				navigablePath,
 				lhs,
@@ -366,18 +369,13 @@ public class AnonymousTupleEmbeddableValuedModelPart implements EmbeddableValued
 	public TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
-		return new StandardVirtualTableGroup(
+		return new StandardVirtualTableGroup( navigablePath, this, lhs, fetched );
-				navigablePath,
-				this,
-				lhs,
-				fetched
-		);
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/query/derived/AnonymousTupleEntityValuedModelPart.java

@@ -70,6 +70,8 @@ import org.hibernate.sql.results.graph.DomainResult;
 import org.hibernate.sql.results.graph.DomainResultCreationState;
 import org.hibernate.type.descriptor.java.JavaType;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 import static java.util.Objects.requireNonNullElse;
 import static org.hibernate.internal.util.collections.CollectionHelper.arrayList;
 
@@ -245,14 +247,13 @@ public class AnonymousTupleEntityValuedModelPart
 	public TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType requestedJoinType,
+			@Nullable SqlAstJoinType requestedJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState) {
 		final SqlAstJoinType joinType = requireNonNullElse( requestedJoinType, SqlAstJoinType.INNER );
-
 		final LazyTableGroup lazyTableGroup = createRootTableGroupJoin(
 				navigablePath,
 				lhs,
@@ -440,11 +441,11 @@ public class AnonymousTupleEntityValuedModelPart
 	public LazyTableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState) {
 		final SqlAliasBase sqlAliasBase = SqlAliasBase.from(
 				explicitSqlAliasBase,

hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmUtil.java

@@ -41,8 +41,11 @@ import org.hibernate.metamodel.model.domain.BasicDomainType;
 import org.hibernate.metamodel.model.domain.DomainType;
 import org.hibernate.metamodel.model.domain.EntityDomainType;
 import org.hibernate.metamodel.model.domain.IdentifiableDomainType;
+import org.hibernate.metamodel.model.domain.ManagedDomainType;
 import org.hibernate.metamodel.model.domain.SimpleDomainType;
+import org.hibernate.metamodel.model.domain.SingularPersistentAttribute;
 import org.hibernate.metamodel.model.domain.internal.EntitySqmPathSource;
+import org.hibernate.persister.entity.EntityPersister;
 import org.hibernate.query.IllegalQueryOperationException;
 import org.hibernate.query.IllegalSelectQueryException;
 import org.hibernate.query.Order;
@@ -63,6 +66,7 @@ import org.hibernate.query.sqm.tree.SqmDmlStatement;
 import org.hibernate.query.sqm.tree.SqmJoinType;
 import org.hibernate.query.sqm.tree.SqmStatement;
 import org.hibernate.query.sqm.tree.domain.SqmPath;
+import org.hibernate.query.sqm.tree.domain.SqmSingularJoin;
 import org.hibernate.query.sqm.tree.expression.JpaCriteriaParameter;
 import org.hibernate.query.sqm.tree.expression.SqmAliasedNodeRef;
 import org.hibernate.query.sqm.tree.expression.SqmExpression;
@@ -101,6 +105,7 @@ import org.hibernate.type.internal.ConvertedBasicTypeImpl;
 import org.hibernate.type.spi.TypeConfiguration;
 
 import jakarta.persistence.Tuple;
+import jakarta.persistence.metamodel.Type;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import static java.util.stream.Collectors.toList;
@@ -188,7 +193,7 @@ public class SqmUtil {
 					// we need to render the target side if in group/order by
 					if ( association.getTargetKeyPropertyNames().contains( sqmPath.getReferencedPathSource().getPathName() )
 							&& ( clause == Clause.GROUP || clause == Clause.ORDER
-							|| !isFkOptimizationAllowed( sqmPath.getLhs() )
+							|| !isFkOptimizationAllowed( sqmPath.getLhs(), association )
 							|| queryPart.getFirstQuerySpec().groupByClauseContains( sqmPath.getNavigablePath(), sqlAstCreationState )
 							|| queryPart.getFirstQuerySpec().orderByClauseContains( sqmPath.getNavigablePath(), sqlAstCreationState ) ) ) {
 						return association.getAssociatedEntityMappingType();
@@ -217,17 +222,106 @@ public class SqmUtil {
 	 * a join that cannot be dereferenced through the foreign key on the associated table,
 	 * i.e. a join that's neither {@linkplain SqmJoinType#INNER} nor {@linkplain SqmJoinType#LEFT}
 	 * or one that has an explicit on clause predicate.
+	 *
+	 * @deprecated Use {@link #isFkOptimizationAllowed(SqmPath, EntityAssociationMapping)} instead
 	 */
+	@Deprecated(forRemoval = true, since = "6.6.1")
 	public static boolean isFkOptimizationAllowed(SqmPath<?> sqmPath) {
-		if ( sqmPath instanceof SqmJoin<?, ?> sqmJoin ) {
+		if ( sqmPath instanceof SqmJoin<?, ?> ) {
-			return switch ( sqmJoin.getSqmJoinType() ) {
+			final SqmJoin<?, ?> sqmJoin = (SqmJoin<?, ?>) sqmPath;
-				case INNER, LEFT -> sqmJoin.getJoinPredicate() == null;
+			switch ( sqmJoin.getSqmJoinType() ) {
-				default -> false;
+				case LEFT:
-			};
+					final EntityAssociationMapping associationMapping = resolveAssociationMapping( sqmJoin );
+					if ( associationMapping != null && isFiltered( associationMapping ) ) {
+						return false;
+					}
+					// FallThrough intended
+				case INNER:
+					return sqmJoin.getJoinPredicate() == null;
+				default:
+					return false;
+			}
 		}
 		return false;
 	}
 
+	/**
+	 * Utility that returns {@code false} when the provided {@link SqmPath sqmPath} is
+	 * a join that cannot be dereferenced through the foreign key on the associated table,
+	 * i.e. a join that's neither {@linkplain SqmJoinType#INNER} nor {@linkplain SqmJoinType#LEFT}
+	 * or one that has an explicit on clause predicate.
+	 */
+	public static boolean isFkOptimizationAllowed(SqmPath<?> sqmPath, EntityAssociationMapping associationMapping) {
+		if ( sqmPath instanceof SqmJoin<?, ?> ) {
+			final SqmJoin<?, ?> sqmJoin = (SqmJoin<?, ?>) sqmPath;
+			switch ( sqmJoin.getSqmJoinType() ) {
+				case LEFT:
+					if ( isFiltered( associationMapping ) ) {
+						return false;
+					}
+					// FallThrough intended
+				case INNER:
+					return sqmJoin.getJoinPredicate() == null;
+				default:
+					return false;
+			}
+		}
+		return false;
+	}
+
+	private static boolean isFiltered(EntityAssociationMapping associationMapping) {
+			final EntityMappingType entityMappingType = associationMapping.getAssociatedEntityMappingType();
+			return !associationMapping.isFkOptimizationAllowed()
+					// When the identifier mappings are different we have a joined subclass entity
+					// which will filter rows based on a discriminator predicate
+					|| entityMappingType.getIdentifierMappingForJoin() != entityMappingType.getIdentifierMapping();
+	}
+
+	private static @Nullable EntityAssociationMapping resolveAssociationMapping(SqmJoin<?, ?> sqmJoin) {
+		if ( sqmJoin instanceof SqmSingularJoin<?, ?> ) {
+			final SqmSingularJoin<?, ?> singularJoin = (SqmSingularJoin<?, ?>) sqmJoin;
+			if ( singularJoin.getAttribute().getSqmPathType() instanceof EntityDomainType<?> ) {
+				return resolveAssociationMapping( singularJoin );
+			}
+		}
+		return null;
+	}
+
+	private static @Nullable EntityAssociationMapping resolveAssociationMapping(SqmSingularJoin<?, ?> sqmJoin) {
+		SingularPersistentAttribute<?, ?> attribute = sqmJoin.getAttribute();
+		ManagedDomainType<?> declaringType = attribute.getDeclaringType();
+		if ( declaringType.getPersistenceType() != Type.PersistenceType.ENTITY ) {
+			final StringBuilder pathBuilder = new StringBuilder();
+			do {
+				if ( pathBuilder.length() > 0 ) {
+					pathBuilder.insert(0, '.');
+				}
+				pathBuilder.insert( 0, attribute.getName() );
+				final SqmFrom<?, ?> lhs = sqmJoin.getLhs();
+				if ( !(lhs instanceof SqmSingularJoin<?, ?> ) ) {
+					return null;
+				}
+				sqmJoin = (SqmSingularJoin<?, ?>) lhs;
+				attribute = sqmJoin.getAttribute();
+				declaringType = attribute.getDeclaringType();
+			} while (declaringType.getPersistenceType() != Type.PersistenceType.ENTITY );
+			pathBuilder.insert(0, '.');
+			pathBuilder.insert( 0, attribute.getName() );
+			final EntityPersister entityDescriptor = sqmJoin.nodeBuilder()
+					.getSessionFactory()
+					.getMappingMetamodel()
+					.getEntityDescriptor( ( (EntityDomainType<?>) declaringType ).getHibernateEntityName() );
+			return (EntityAssociationMapping) entityDescriptor.findByPath( pathBuilder.toString() );
+		}
+		else {
+			final EntityPersister entityDescriptor = sqmJoin.nodeBuilder()
+					.getSessionFactory()
+					.getMappingMetamodel()
+					.getEntityDescriptor( ( (EntityDomainType<?>) declaringType ).getHibernateEntityName() );
+			return (EntityAssociationMapping) entityDescriptor.findAttributeMapping( attribute.getName() );
+		}
+	}
+
 	public static List<NavigablePath> getWhereClauseNavigablePaths(SqmQuerySpec<?> querySpec) {
 		final SqmWhereClause where = querySpec.getWhereClause();
 		if ( where == null || where.getPredicate() == null ) {

hibernate-core/src/main/java/org/hibernate/query/sqm/sql/BaseSqmToSqlAstConverter.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.query.sqm.sql;
 
+import jakarta.annotation.Nullable;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.sql.PreparedStatement;
@@ -28,7 +29,6 @@ import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
-
 import org.hibernate.HibernateException;
 import org.hibernate.Internal;
 import org.hibernate.LockMode;
@@ -3922,7 +3922,7 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 							this
 					);
 					// Implicit joins in the ON clause need to be added as nested table group joins
-					final boolean nested = currentClauseStack.getCurrent() == Clause.FROM;
+					final boolean nested = currentlyProcessingJoin != null;
 					if ( nested ) {
 						parentTableGroup.addNestedTableGroupJoin( tableGroupJoin );
 					}
@@ -3996,6 +3996,13 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 		}
 	}
 
+	@Override
+	public @Nullable SqlAstJoinType getCurrentlyProcessingJoinType() {
+		return currentlyProcessingJoin == null
+				? null
+				: currentlyProcessingJoin.getSqmJoinType().getCorrespondingSqlJoinType();
+	}
+
 	// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 	// SqmPath handling
 	//		- Note that SqmFrom references defined in the FROM-clause are already
@@ -4125,8 +4132,7 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 				// When the inferred mapping is null, we try to resolve to the FK by default, which is fine because
 				// expansion to all target columns for select and group by clauses is handled in EntityValuedPathInterpretation
 				if ( entityValuedModelPart instanceof EntityAssociationMapping
-						&& ( (EntityAssociationMapping) entityValuedModelPart ).isFkOptimizationAllowed()
+						&& isFkOptimizationAllowed( path, (EntityAssociationMapping) entityValuedModelPart ) ) {
-						&& isFkOptimizationAllowed( path ) ) {
 					// If the table group uses an association mapping that is not a one-to-many,
 					// we make use of the FK model part - unless the path is a non-optimizable join,
 					// for which we should always use the target's identifier to preserve semantics
@@ -8401,7 +8407,7 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 							final TableGroupJoinProducer joinProducer = (TableGroupJoinProducer) fetchable;
 							final TableGroup compatibleTableGroup = lhs.findCompatibleJoinedGroup(
 									joinProducer,
-									joinProducer.determineSqlJoinType( lhs, null, true )
+									joinProducer.getDefaultSqlAstJoinType( lhs )
 							);
 							final SqmQueryPart<?> queryPart = getCurrentSqmQueryPart();
 							if ( compatibleTableGroup == null

hibernate-core/src/main/java/org/hibernate/query/sqm/sql/FakeSqmToSqlAstConverter.java

@@ -21,6 +21,7 @@ import org.hibernate.query.sqm.tree.expression.SqmParameter;
 import org.hibernate.query.sqm.tree.predicate.SqmPredicate;
 import org.hibernate.query.sqm.tree.select.SqmQueryPart;
 import org.hibernate.sql.ast.Clause;
+import org.hibernate.sql.ast.SqlAstJoinType;
 import org.hibernate.sql.ast.spi.FromClauseAccess;
 import org.hibernate.sql.ast.spi.SqlAliasBaseGenerator;
 import org.hibernate.sql.ast.spi.SqlAstCreationContext;
@@ -31,6 +32,8 @@ import org.hibernate.sql.ast.tree.expression.Expression;
 import org.hibernate.sql.ast.tree.expression.QueryTransformer;
 import org.hibernate.sql.ast.tree.predicate.Predicate;
 
+import jakarta.annotation.Nullable;
+
 /**
  *
  */
@@ -101,6 +104,11 @@ public class FakeSqmToSqlAstConverter extends BaseSemanticQueryWalker implements
 	public void registerQueryTransformer(QueryTransformer transformer) {
 	}
 
+	@Override
+	public @Nullable SqlAstJoinType getCurrentlyProcessingJoinType() {
+		return null;
+	}
+
 	@Override
 	public boolean isInTypeInference() {
 		return false;

hibernate-core/src/main/java/org/hibernate/query/sqm/sql/SqmToSqlAstConverter.java

@@ -18,6 +18,7 @@ import org.hibernate.query.sqm.tree.expression.SqmExpression;
 import org.hibernate.query.sqm.tree.expression.SqmParameter;
 import org.hibernate.query.sqm.tree.predicate.SqmPredicate;
 import org.hibernate.query.sqm.tree.select.SqmQueryPart;
+import org.hibernate.sql.ast.SqlAstJoinType;
 import org.hibernate.sql.ast.spi.SqlAstCreationState;
 import org.hibernate.sql.ast.Clause;
 import org.hibernate.sql.ast.tree.expression.Expression;
@@ -38,6 +39,12 @@ public interface SqmToSqlAstConverter extends SemanticQueryWalker<Object>, SqlAs
 
 	void registerQueryTransformer(QueryTransformer transformer);
 
+	/**
+	 * Returns the {@link SqlAstJoinType} of the currently processing join if there is one, or {@code null}.
+	 * This is used to determine the join type for implicit joins happening in the {@code ON} clause.
+	 */
+	@Nullable SqlAstJoinType getCurrentlyProcessingJoinType();
+
 	/**
 	 * Returns whether the state of the translation is currently in type inference mode.
 	 * This is useful to avoid type inference based on other incomplete inference information.

hibernate-core/src/main/java/org/hibernate/sql/ast/internal/TableGroupHelper.java

@@ -0,0 +1,282 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+
+package org.hibernate.sql.ast.internal;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.hibernate.internal.util.collections.CollectionHelper;
+import org.hibernate.metamodel.mapping.internal.CaseStatementDiscriminatorMappingImpl;
+import org.hibernate.persister.internal.SqlFragmentPredicate;
+import org.hibernate.sql.ast.spi.AbstractSqlAstWalker;
+import org.hibernate.sql.ast.tree.expression.AggregateColumnWriteExpression;
+import org.hibernate.sql.ast.tree.expression.ColumnReference;
+import org.hibernate.sql.ast.tree.expression.Expression;
+import org.hibernate.sql.ast.tree.expression.SelfRenderingExpression;
+import org.hibernate.sql.ast.tree.expression.SelfRenderingSqlFragmentExpression;
+import org.hibernate.sql.ast.tree.expression.SqlTuple;
+import org.hibernate.sql.ast.tree.expression.SqlTupleContainer;
+import org.hibernate.sql.ast.tree.from.NamedTableReference;
+import org.hibernate.sql.ast.tree.from.TableGroup;
+import org.hibernate.sql.ast.tree.from.TableReference;
+import org.hibernate.sql.ast.tree.from.TableReferenceJoin;
+import org.hibernate.sql.ast.tree.predicate.ComparisonPredicate;
+import org.hibernate.sql.ast.tree.predicate.FilterPredicate;
+import org.hibernate.sql.ast.tree.predicate.Junction;
+import org.hibernate.sql.ast.tree.predicate.Predicate;
+import org.hibernate.sql.model.ast.ColumnWriteFragment;
+
+/**
+ * A simple walker that checks if a predicate contains qualifiers.
+ *
+ * @author Christian Beikov
+ */
+public class TableGroupHelper extends AbstractSqlAstWalker {
+
+	public static final int REAL_TABLE_GROUP_REQUIRED = Integer.MAX_VALUE;
+	public static final int NO_TABLE_GROUP_REQUIRED = -1;
+
+	private final String primaryQualifier;
+	private final Map<String, Integer> qualifiers;
+	private final String[] qualifierFragments;
+	private Integer usedTableReferenceJoinIndex;
+
+	private TableGroupHelper(String primaryQualifier, Map<String, Integer> qualifiers) {
+		this.primaryQualifier = primaryQualifier;
+		this.qualifiers = qualifiers;
+		final String[] qualifierFragments = new String[qualifiers.size()];
+		for ( Map.Entry<String, Integer> entry : qualifiers.entrySet() ) {
+			qualifierFragments[entry.getValue()] = entry.getKey() + ".";
+		}
+		this.qualifierFragments = qualifierFragments;
+	}
+
+	/**
+	 * Returns the index of a table reference join which can be swapped with the primary table reference
+	 * to avoid rendering a real nested table group.
+	 * {@link #REAL_TABLE_GROUP_REQUIRED} is returned if swapping is not possible.
+	 * {@code #NO_TABLE_GROUP_REQUIRED} is returned if no swapping is necessary.
+	 */
+	public static int findReferenceJoinForPredicateSwap(TableGroup tableGroup, Predicate predicate) {
+		if ( predicate != null && !tableGroup.getTableReferenceJoins().isEmpty() ) {
+			final TableReference primaryTableReference = tableGroup.getPrimaryTableReference();
+			final HashMap<String, Integer> qualifiers = CollectionHelper.mapOfSize( tableGroup.getTableReferenceJoins().size() );
+			final List<TableReferenceJoin> tableReferenceJoins = tableGroup.getTableReferenceJoins();
+			for ( int i = 0; i < tableReferenceJoins.size(); i++ ) {
+				final TableReferenceJoin tableReferenceJoin = tableReferenceJoins.get( i );
+				if ( !tableGroup.canUseInnerJoins() ) {
+					if ( !isSimplePredicate( tableGroup, i ) ){//|| isSimpleOrOuterJoin( tableReferenceJoin ) ) {
+						// Can't do avoid the real table group rendering in this case if it's not inner joined,
+						// because doing so might change the meaning of the SQL. Consider this example:
+						// `from tbl1 t1 left join (tbl2 t2 join tbl3 t3 on t2.id=t3.id and ...) on t1.fk=t2.id`
+						//
+						// To avoid the nested table group rendering, the join on `tbl3` has to switch to left join
+						// `from tbl1 t1 left join tbl2 t2 on t1.fk=t2.id left join tbl3 t3 on t2.id=t3.id and ...`
+						// The additional predicate in the `tbl3` join can make `t3` null even though `t2` is non-null
+						return REAL_TABLE_GROUP_REQUIRED;
+					}
+				}
+				qualifiers.put( tableReferenceJoin.getJoinedTableReference().getIdentificationVariable(), i );
+			}
+			final TableGroupHelper qualifierCollector = new TableGroupHelper(
+					primaryTableReference.getIdentificationVariable(),
+					qualifiers
+			);
+			try {
+				predicate.accept( qualifierCollector );
+				if ( qualifierCollector.usedTableReferenceJoinIndex == null ) {
+					return NO_TABLE_GROUP_REQUIRED;
+				}
+				if ( qualifierCollector.usedTableReferenceJoinIndex != NO_TABLE_GROUP_REQUIRED
+						&& !tableGroup.canUseInnerJoins() && !isSimpleTableReference( primaryTableReference ) ) {
+					// Can't reorder table reference join with primary table reference if the primary table reference
+					// might filter out elements, since that affects result count with outer joins
+					return REAL_TABLE_GROUP_REQUIRED;
+				}
+				return qualifierCollector.usedTableReferenceJoinIndex;
+			}
+			catch (MultipleUsesFoundException ex) {
+				return REAL_TABLE_GROUP_REQUIRED;
+			}
+		}
+		return NO_TABLE_GROUP_REQUIRED;
+	}
+
+	private static boolean isSimpleTableReference(TableReference tableReference) {
+		return tableReference instanceof NamedTableReference && !tableReference.getTableId().startsWith( "(select" );
+	}
+
+	/**
+	 * Checks if the table reference join at the given index uses a simple equality join predicate.
+	 * Predicates that contain anything but comparisons of the primary table reference with table reference join columns
+	 * are non-simple.
+	 */
+	private static boolean isSimplePredicate(TableGroup tableGroup, int index) {
+		final TableReference primaryTableReference = tableGroup.getPrimaryTableReference();
+		final TableReferenceJoin tableReferenceJoin = tableGroup.getTableReferenceJoins().get( index );
+		final NamedTableReference joinedTableReference = tableReferenceJoin.getJoinedTableReference();
+		final Predicate predicate = tableReferenceJoin.getPredicate();
+		if ( predicate instanceof Junction ) {
+			final Junction junction = (Junction) predicate;
+			if ( junction.getNature() == Junction.Nature.CONJUNCTION ) {
+				for ( Predicate subPredicate : junction.getPredicates() ) {
+					if ( !isComparison( subPredicate, primaryTableReference, joinedTableReference ) ) {
+						return false;
+					}
+				}
+				return true;
+			}
+		}
+		else {
+			return isComparison( predicate, primaryTableReference, joinedTableReference );
+		}
+		return false;
+	}
+
+	private static boolean isComparison(Predicate predicate, TableReference table1, TableReference table2) {
+		if ( predicate instanceof ComparisonPredicate ) {
+			final ComparisonPredicate comparisonPredicate = (ComparisonPredicate) predicate;
+			final Expression lhs = comparisonPredicate.getLeftHandExpression();
+			final Expression rhs = comparisonPredicate.getRightHandExpression();
+			final SqlTuple lhsTuple;
+			if ( lhs instanceof SqlTupleContainer && ( lhsTuple = ( (SqlTupleContainer) lhs ).getSqlTuple() ) != null ) {
+				final SqlTuple rhsTuple = ( (SqlTupleContainer) rhs ).getSqlTuple();
+				final List<? extends Expression> lhsExpressions = lhsTuple.getExpressions();
+				final List<? extends Expression> rhsExpressions = rhsTuple.getExpressions();
+				for ( int i = 0; i < lhsExpressions.size(); i++ ) {
+					final ColumnReference lhsColumn = lhsExpressions.get( i ).getColumnReference();
+					final ColumnReference rhsColumn = rhsExpressions.get( i ).getColumnReference();
+					if ( !isComparison( table1, table2, lhsColumn, rhsColumn ) ) {
+						return false;
+					}
+				}
+				return true;
+			}
+			else {
+				return isComparison( table1, table2, lhs.getColumnReference(), rhs.getColumnReference() );
+			}
+		}
+		return false;
+	}
+
+	private static boolean isComparison(
+			TableReference table1,
+			TableReference table2,
+			ColumnReference column1,
+			ColumnReference column2) {
+		if ( column1 != null && column2 != null ) {
+			final String column1Qualifier = column1.getQualifier();
+			final String column2Qualifier = column2.getQualifier();
+			final String table1Qualifier = table1.getIdentificationVariable();
+			final String table2Qualifier = table2.getIdentificationVariable();
+			return column1Qualifier.equals( table1Qualifier ) && column2Qualifier.equals( table2Qualifier )
+					|| column1Qualifier.equals( table2Qualifier ) && column2Qualifier.equals( table1Qualifier );
+		}
+		return false;
+	}
+
+	private static class MultipleUsesFoundException extends RuntimeException {
+		public MultipleUsesFoundException() {
+		}
+
+		@Override
+		public Throwable fillInStackTrace() {
+			return this;
+		}
+	}
+
+	private void checkQualifier(String qualifier) {
+		if ( primaryQualifier.equals( qualifier ) ) {
+			if ( usedTableReferenceJoinIndex != null && usedTableReferenceJoinIndex != NO_TABLE_GROUP_REQUIRED ) {
+				throw new MultipleUsesFoundException();
+			}
+			usedTableReferenceJoinIndex = NO_TABLE_GROUP_REQUIRED;
+		}
+		else {
+			final Integer index = qualifiers.get( qualifier );
+			if ( index != null ) {
+				if ( usedTableReferenceJoinIndex != null && usedTableReferenceJoinIndex.intValue() != index ) {
+					throw new MultipleUsesFoundException();
+				}
+				usedTableReferenceJoinIndex = index;
+			}
+		}
+	}
+
+	private void checkSql(String sql) {
+		if ( sql.contains( primaryQualifier + "." ) ) {
+			if ( usedTableReferenceJoinIndex != null && usedTableReferenceJoinIndex != NO_TABLE_GROUP_REQUIRED ) {
+				throw new MultipleUsesFoundException();
+			}
+			usedTableReferenceJoinIndex = NO_TABLE_GROUP_REQUIRED;
+		}
+		else {
+			for ( int i = 0; i < qualifierFragments.length; i++ ) {
+				if ( sql.contains( qualifierFragments[i] ) ) {
+					if ( usedTableReferenceJoinIndex != null && usedTableReferenceJoinIndex != i ) {
+						throw new MultipleUsesFoundException();
+					}
+					usedTableReferenceJoinIndex = i;
+				}
+			}
+		}
+	}
+
+	@Override
+	public void visitSelfRenderingExpression(SelfRenderingExpression expression) {
+		if ( expression instanceof SelfRenderingSqlFragmentExpression ) {
+			checkSql( ( (SelfRenderingSqlFragmentExpression) expression ).getExpression() );
+		}
+		else if ( expression instanceof CaseStatementDiscriminatorMappingImpl.CaseStatementDiscriminatorExpression ) {
+			for ( TableReference usedTableReference : ( (CaseStatementDiscriminatorMappingImpl.CaseStatementDiscriminatorExpression) expression ).getUsedTableReferences() ) {
+				usedTableReference.accept( this );
+			}
+		}
+		else {
+			super.visitSelfRenderingExpression( expression );
+		}
+	}
+
+	@Override
+	public void visitNamedTableReference(NamedTableReference tableReference) {
+		checkQualifier( tableReference.getIdentificationVariable() );
+	}
+
+	@Override
+	public void visitColumnReference(ColumnReference columnReference) {
+		checkQualifier( columnReference.getQualifier() );
+	}
+
+	@Override
+	public void visitAggregateColumnWriteExpression(AggregateColumnWriteExpression aggregateColumnWriteExpression) {
+		checkQualifier( aggregateColumnWriteExpression.getAggregateColumnReference().getQualifier() );
+	}
+
+	@Override
+	public void visitFilterPredicate(FilterPredicate filterPredicate) {
+		for ( FilterPredicate.FilterFragmentPredicate fragment : filterPredicate.getFragments() ) {
+			visitFilterFragmentPredicate( fragment );
+		}
+	}
+
+	@Override
+	public void visitFilterFragmentPredicate(FilterPredicate.FilterFragmentPredicate fragmentPredicate) {
+		checkSql( fragmentPredicate.getSqlFragment() );
+	}
+
+	@Override
+	public void visitSqlFragmentPredicate(SqlFragmentPredicate predicate) {
+		checkSql( predicate.getSqlFragment() );
+	}
+
+	@Override
+	public void visitColumnWriteFragment(ColumnWriteFragment columnWriteFragment) {
+		checkSql( columnWriteFragment.getFragment() );
+	}
+}

hibernate-core/src/main/java/org/hibernate/sql/ast/spi/AbstractSqlAstTranslator.java

@@ -88,6 +88,7 @@ import org.hibernate.sql.ast.SqlAstJoinType;
 import org.hibernate.sql.ast.SqlAstNodeRenderingMode;
 import org.hibernate.sql.ast.SqlAstTranslator;
 import org.hibernate.sql.ast.SqlTreeCreationException;
+import org.hibernate.sql.ast.internal.TableGroupHelper;
 import org.hibernate.sql.ast.internal.ParameterMarkerStrategyStandard;
 import org.hibernate.sql.ast.tree.AbstractUpdateOrDeleteStatement;
 import org.hibernate.sql.ast.tree.MutationStatement;
@@ -6034,10 +6035,60 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 	}
 
 	protected void renderTableGroup(TableGroup tableGroup, Predicate predicate, List<TableGroupJoin> tableGroupJoinCollector) {
-		// Without reference joins or nested join groups, even a real table group does not need parenthesis
+		final boolean realTableGroup;
-		final boolean realTableGroup = tableGroup.isRealTableGroup()
+		int swappedJoinIndex = -1;
-				&& ( CollectionHelper.isNotEmpty( tableGroup.getTableReferenceJoins() )
+		boolean forceLeftJoin = false;
-				|| hasNestedTableGroupsToRender( tableGroup.getNestedTableGroupJoins() ) );
+		if ( tableGroup.isRealTableGroup() ) {
+			if ( hasNestedTableGroupsToRender( tableGroup.getNestedTableGroupJoins() ) ) {
+				// If there are nested table groups, we need to render a real table group
+				realTableGroup = true;
+			}
+			else {
+				// Determine the reference join indexes of the table reference used in the predicate
+				final int referenceJoinIndexForPredicateSwap = TableGroupHelper.findReferenceJoinForPredicateSwap(
+						tableGroup,
+						predicate
+				);
+				if ( referenceJoinIndexForPredicateSwap == TableGroupHelper.REAL_TABLE_GROUP_REQUIRED ) {
+					// Means that real table group rendering is necessary
+					realTableGroup = true;
+				}
+				else if ( referenceJoinIndexForPredicateSwap == TableGroupHelper.NO_TABLE_GROUP_REQUIRED ) {
+					// Means that no swap is necessary to avoid the table group rendering
+					realTableGroup = false;
+					forceLeftJoin = !tableGroup.canUseInnerJoins();
+				}
+				else {
+					// Means that real table group rendering can be avoided if the primary table reference is swapped
+					// with the table reference join at the given index
+					realTableGroup = false;
+					forceLeftJoin = !tableGroup.canUseInnerJoins();
+					swappedJoinIndex = referenceJoinIndexForPredicateSwap;
+
+					// Render the table reference of the table reference join first
+					final TableReferenceJoin tableReferenceJoin = tableGroup.getTableReferenceJoins().get( swappedJoinIndex );
+					renderNamedTableReference( tableReferenceJoin.getJoinedTableReference(), LockMode.NONE );
+					// along with the predicate for the table group
+					if ( predicate != null ) {
+						appendSql( " on " );
+						predicate.accept( this );
+					}
+
+					// Then render the join syntax and fall through to rendering the primary table reference
+					appendSql( WHITESPACE );
+					if ( tableGroup.canUseInnerJoins() ) {
+						appendSql( tableReferenceJoin.getJoinType().getText() );
+					}
+					else {
+						append( "left " );
+					}
+					appendSql( "join " );
+				}
+			}
+		}
+		else {
+			realTableGroup = false;
+		}
 		if ( realTableGroup ) {
 			appendSql( OPEN_PARENTHESIS );
 		}
@@ -6065,7 +6116,8 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 			tableGroupJoins = null;
 		}
 
-		if ( predicate != null ) {
+		// Predicate was already rendered when swappedJoinIndex is not equal to -1
+		if ( predicate != null && swappedJoinIndex == -1 ) {
 			appendSql( " on " );
 			predicate.accept( this );
 		}
@@ -6083,7 +6135,7 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 		}
 
 		if ( !realTableGroup ) {
-			renderTableReferenceJoins( tableGroup );
+			renderTableReferenceJoins( tableGroup, swappedJoinIndex, forceLeftJoin );
 			processNestedTableGroupJoins( tableGroup, tableGroupJoinCollector );
 		}
 		if ( tableGroupJoinCollector != null ) {
@@ -6362,21 +6414,43 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 	}
 
 	protected void renderTableReferenceJoins(TableGroup tableGroup) {
+		renderTableReferenceJoins( tableGroup, -1, false );
+	}
+
+	protected void renderTableReferenceJoins(TableGroup tableGroup, int swappedJoinIndex, boolean forceLeftJoin) {
 		final List<TableReferenceJoin> joins = tableGroup.getTableReferenceJoins();
 		if ( joins == null || joins.isEmpty() ) {
 			return;
 		}
 
-		for ( TableReferenceJoin tableJoin : joins ) {
+		if ( swappedJoinIndex != -1 ) {
-			appendSql( WHITESPACE );
+			// Finish the join against the primary table reference after the swap
-			appendSql( tableJoin.getJoinType().getText() );
+			final TableReferenceJoin swappedJoin = joins.get( swappedJoinIndex );
-			appendSql( "join " );
+			if ( swappedJoin.getPredicate() != null && !swappedJoin.getPredicate().isEmpty() ) {
-
-			renderNamedTableReference( tableJoin.getJoinedTableReference(), LockMode.NONE );
-
-			if ( tableJoin.getPredicate() != null && !tableJoin.getPredicate().isEmpty() ) {
 				appendSql( " on " );
-				tableJoin.getPredicate().accept( this );
+				swappedJoin.getPredicate().accept( this );
+			}
+		}
+
+		for ( int i = 0; i < joins.size(); i++ ) {
+			// Skip the swapped join since it was already rendered
+			if ( swappedJoinIndex != i ) {
+				final TableReferenceJoin tableJoin = joins.get( i );
+				appendSql( WHITESPACE );
+				if ( forceLeftJoin ) {
+					append( "left " );
+				}
+				else {
+					appendSql( tableJoin.getJoinType().getText() );
+				}
+				appendSql( "join " );
+
+				renderNamedTableReference( tableJoin.getJoinedTableReference(), LockMode.NONE );
+
+				if ( tableJoin.getPredicate() != null && !tableJoin.getPredicate().isEmpty() ) {
+					appendSql( " on " );
+					tableJoin.getPredicate().accept( this );
+				}
 			}
 		}
 	}

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/OneToManyTableGroup.java

@@ -63,9 +63,18 @@ public class OneToManyTableGroup extends AbstractColumnReferenceQualifier implem
 	}
 
 	public void registerIndexTableGroup(TableGroupJoin indexTableGroupJoin) {
+		registerIndexTableGroup( indexTableGroupJoin, true );
+	}
+
+	public void registerIndexTableGroup(TableGroupJoin indexTableGroupJoin, boolean nested) {
 		assert this.indexTableGroup == null;
 		this.indexTableGroup = indexTableGroupJoin.getJoinedGroup();
-		addNestedTableGroupJoin( indexTableGroupJoin );
+		if ( nested ) {
+			addNestedTableGroupJoin( indexTableGroupJoin );
+		}
+		else {
+			addTableGroupJoin( indexTableGroupJoin );
+		}
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/from/TableGroupJoinProducer.java

@@ -12,10 +12,11 @@ import org.hibernate.spi.NavigablePath;
 import org.hibernate.sql.ast.SqlAstJoinType;
 import org.hibernate.sql.ast.spi.SqlAliasBase;
 import org.hibernate.sql.ast.spi.SqlAliasBaseGenerator;
-import org.hibernate.sql.ast.spi.SqlAstCreationContext;
 import org.hibernate.sql.ast.spi.SqlAstCreationState;
 import org.hibernate.sql.ast.tree.predicate.Predicate;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * @author Steve Ebersole
  */
@@ -41,9 +42,9 @@ public interface TableGroupJoinProducer extends TableGroupProducer {
 	TableGroupJoin createTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
 			boolean addsPredicate,
 			SqlAstCreationState creationState);
@@ -70,14 +71,14 @@ public interface TableGroupJoinProducer extends TableGroupProducer {
 	TableGroup createRootTableGroupJoin(
 			NavigablePath navigablePath,
 			TableGroup lhs,
-			String explicitSourceAlias,
+			@Nullable String explicitSourceAlias,
-			SqlAliasBase explicitSqlAliasBase,
+			@Nullable SqlAliasBase explicitSqlAliasBase,
-			SqlAstJoinType sqlAstJoinType,
+			@Nullable SqlAstJoinType sqlAstJoinType,
 			boolean fetched,
-			Consumer<Predicate> predicateConsumer,
+			@Nullable Consumer<Predicate> predicateConsumer,
 			SqlAstCreationState creationState);
 
-	default SqlAstJoinType determineSqlJoinType(TableGroup lhs, SqlAstJoinType requestedJoinType, boolean fetched) {
+	default SqlAstJoinType determineSqlJoinType(TableGroup lhs, @Nullable SqlAstJoinType requestedJoinType, boolean fetched) {
 		if ( requestedJoinType != null ) {
 			return requestedJoinType;
 		}

hibernate-core/src/main/java/org/hibernate/type/descriptor/DateTimeUtils.java

@@ -458,7 +458,10 @@ public final class DateTimeUtils {
 	/**
 	 * Do the same conversion that databases do when they encounter a timestamp with a higher precision
 	 * than what is supported by a column, which is to round the excess fractions.
+	 *
+	 * @deprecated Use {@link #adjustToDefaultPrecision(Temporal, Dialect)} instead
 	 */
+	@Deprecated(forRemoval = true, since = "6.6.1")
 	public static <T extends Temporal> T roundToDefaultPrecision(T temporal, Dialect d) {
 		final int defaultTimestampPrecision = d.getDefaultTimestampPrecision();
 		if ( defaultTimestampPrecision >= 9 || !temporal.isSupported( ChronoField.NANO_OF_SECOND ) ) {
@@ -472,6 +475,9 @@ public final class DateTimeUtils {
 	}
 
 	public static <T extends Temporal> T roundToSecondPrecision(T temporal, int precision) {
+		if ( precision >= 9 || !temporal.isSupported( ChronoField.NANO_OF_SECOND ) ) {
+			return temporal;
+		}
 		if ( precision == 0 ) {
 			//noinspection unchecked
 			return temporal.get( ChronoField.NANO_OF_SECOND ) >= 500_000_000L

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/refcolnames/secondary/RefToSecondaryTableTest.java

@@ -5,10 +5,8 @@ import org.hibernate.testing.orm.junit.DomainModel;
 import org.hibernate.testing.orm.junit.SessionFactory;
 import org.hibernate.testing.orm.junit.SessionFactoryScope;
 import org.junit.jupiter.api.Assertions;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
-//@Disabled("test produces broken SQL and issue needs to be fixed")
 @TestForIssue(jiraKey = "HHH-15933")
 @SessionFactory
 @DomainModel(annotatedClasses = { Split.class, Reference.class })

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/join/AttributeJoinWithJoinedInheritanceTest.java

@@ -57,6 +57,33 @@ public class AttributeJoinWithJoinedInheritanceTest {
 		} );
 	}
 
+	@Test
+	@Jira( "https://hibernate.atlassian.net/browse/HHH-17646" )
+	public void testLeftJoinSelectFk(SessionFactoryScope scope) {
+		scope.inTransaction( s -> {
+			final ChildEntityA childEntityA = new SubChildEntityA1( 11 );
+			s.persist( childEntityA );
+			final ChildEntityB childEntityB = new ChildEntityB( 21 );
+			s.persist( childEntityB );
+			s.persist( new RootOne( 1, childEntityA ) );
+			s.persist( new RootOne( 2, null ) );
+		} );
+		scope.inTransaction( s -> {
+			// simulate association with ChildEntityB
+			s.createNativeMutationQuery( "update root_one set child_id = 21 where id = 2" ).executeUpdate();
+		} );
+		scope.inTransaction( s -> {
+			final List<Integer> resultList = s.createQuery(
+					"select ce.id " +
+							"from RootOne r left join r.child ce ",
+					Integer.class
+			).getResultList();
+			assertEquals( 2, resultList.size() );
+			assertEquals( 11, resultList.get( 0 ) );
+			assertNull( resultList.get( 1 ) );
+		} );
+	}
+
 	@Test
 	public void testLeftJoin(SessionFactoryScope scope) {
 		scope.inTransaction( s -> {

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/join/AttributeJoinWithNaturalJoinedInheritanceTest.java

@@ -0,0 +1,225 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.orm.test.inheritance.join;
+
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.DiscriminatorColumn;
+import jakarta.persistence.DiscriminatorValue;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.Tuple;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+@DomainModel( annotatedClasses = {
+		AttributeJoinWithNaturalJoinedInheritanceTest.BaseClass.class,
+		AttributeJoinWithNaturalJoinedInheritanceTest.ChildEntityA.class,
+		AttributeJoinWithNaturalJoinedInheritanceTest.SubChildEntityA1.class,
+		AttributeJoinWithNaturalJoinedInheritanceTest.SubChildEntityA2.class,
+		AttributeJoinWithNaturalJoinedInheritanceTest.ChildEntityB.class,
+		AttributeJoinWithNaturalJoinedInheritanceTest.RootOne.class
+} )
+@SessionFactory
+@Jira( "https://hibernate.atlassian.net/browse/HHH-17646" )
+public class AttributeJoinWithNaturalJoinedInheritanceTest {
+	@AfterEach
+	public void cleanup(SessionFactoryScope scope) {
+		scope.inTransaction( s -> {
+			s.createMutationQuery( "delete from RootOne" ).executeUpdate();
+			s.createMutationQuery( "delete from SubChildEntityA1" ).executeUpdate();
+			s.createMutationQuery( "delete from SubChildEntityA2" ).executeUpdate();
+			s.createMutationQuery( "delete from BaseClass" ).executeUpdate();
+		} );
+	}
+
+	@Test
+	public void testLeftJoinWithDiscriminatorFiltering(SessionFactoryScope scope) {
+		scope.inTransaction( s -> {
+			final ChildEntityA childEntityA1 = new SubChildEntityA1( 11 );
+			s.persist( childEntityA1 );
+			final ChildEntityA childEntityA2 = new SubChildEntityA2( 21 );
+			s.persist( childEntityA2 );
+			s.persist( new RootOne( 1, childEntityA1 ) );
+			s.persist( new RootOne( 2, childEntityA2 ) );
+		} );
+		scope.inTransaction( s -> {
+			final List<Tuple> resultList = s.createQuery(
+					"select r, ce, ce.uk " +
+							"from RootOne r left join treat(r.child as SubChildEntityA1) ce " +
+							"order by r.id",
+					Tuple.class
+			).getResultList();
+			assertEquals( 2, resultList.size() );
+			assertResult( resultList.get( 0 ), 1, 11, 11, "child_a_1", SubChildEntityA1.class, 11 );
+			assertResult( resultList.get( 1 ), 2, 21, null, null, null, null );
+		} );
+	}
+
+	private <T extends ChildEntityA> void assertResult(
+			Tuple result,
+			Integer rootId,
+			Integer rootChildId,
+			Integer childId,
+			String discValue,
+			Class<T> subClass,
+			Integer uk) {
+		if ( rootId != null ) {
+			final RootOne root = result.get( 0, RootOne.class );
+			assertEquals( rootId, root.getId() );
+			assertEquals( rootChildId, root.getChildId() );
+		}
+		else {
+			assertNull( result.get( 0 ) );
+		}
+		if ( subClass != null ) {
+			assertInstanceOf( subClass, result.get( 1 ) );
+			final ChildEntityA sub1 = result.get( 1, subClass );
+			assertEquals( childId, sub1.getId() );
+			assertEquals( discValue, sub1.getDiscCol() );
+		}
+		else {
+			assertNull( result.get( 1 ) );
+		}
+		if ( uk != null ) {
+			assertEquals( uk, result.get( 2 ) );
+		}
+		else {
+			assertNull( result.get( 2 ) );
+		}
+	}
+
+	/**
+	 * NOTE: We define a {@link DiscriminatorColumn} to allow multiple subclasses
+	 * to share the same table name. This will need additional care when pruning
+	 * the table expression, since we'll have to add the discriminator condition
+	 * before joining with the subclass tables
+	 */
+	@Entity( name = "BaseClass" )
+	@Inheritance( strategy = InheritanceType.JOINED )
+	@DiscriminatorColumn( name = "disc_col" )
+	public static class BaseClass {
+		@Id
+		private Integer id;
+
+		@Column( name = "disc_col", insertable = false, updatable = false )
+		private String discCol;
+
+		public BaseClass() {
+		}
+
+		public BaseClass(Integer id) {
+			this.id = id;
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public String getDiscCol() {
+			return discCol;
+		}
+	}
+
+	@Entity( name = "ChildEntityA" )
+	@Table( name = "child_entity" )
+	public static abstract class ChildEntityA extends BaseClass {
+		@Column(unique = true)
+		private Integer uk;
+
+		public ChildEntityA() {
+		}
+
+		public ChildEntityA(Integer id) {
+			super( id );
+			this.uk = id;
+		}
+
+		public Integer getUk() {
+			return uk;
+		}
+	}
+
+	@Entity( name = "SubChildEntityA1" )
+	@DiscriminatorValue( "child_a_1" )
+	public static class SubChildEntityA1 extends ChildEntityA {
+		public SubChildEntityA1() {
+		}
+
+		public SubChildEntityA1(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "SubChildEntityA2" )
+	@DiscriminatorValue( "child_a_2" )
+	public static class SubChildEntityA2 extends ChildEntityA {
+		public SubChildEntityA2() {
+		}
+
+		public SubChildEntityA2(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "ChildEntityB" )
+	@Table( name = "child_entity" )
+	public static class ChildEntityB extends BaseClass {
+
+		public ChildEntityB() {
+		}
+
+		public ChildEntityB(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "RootOne" )
+	@Table( name = "root_one" )
+	public static class RootOne {
+		@Id
+		private Integer id;
+
+		@Column( name = "child_id", insertable = false, updatable = false )
+		private Integer childId;
+
+		@ManyToOne
+		@JoinColumn( name = "child_id", referencedColumnName = "uk")
+		private ChildEntityA child;
+
+		public RootOne() {
+		}
+
+		public RootOne(Integer id, ChildEntityA child) {
+			this.id = id;
+			this.child = child;
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public Integer getChildId() {
+			return childId;
+		}
+	}
+}

hibernate-core/src/test/java/org/hibernate/orm/test/inheritance/join/AttributeJoinWithRestrictedJoinedInheritanceTest.java

@@ -0,0 +1,215 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.orm.test.inheritance.join;
+
+import java.util.List;
+
+import org.hibernate.annotations.SQLRestriction;
+
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.DiscriminatorColumn;
+import jakarta.persistence.DiscriminatorValue;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.Tuple;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+@DomainModel( annotatedClasses = {
+		AttributeJoinWithRestrictedJoinedInheritanceTest.BaseClass.class,
+		AttributeJoinWithRestrictedJoinedInheritanceTest.ChildEntityA.class,
+		AttributeJoinWithRestrictedJoinedInheritanceTest.SubChildEntityA1.class,
+		AttributeJoinWithRestrictedJoinedInheritanceTest.SubChildEntityA2.class,
+		AttributeJoinWithRestrictedJoinedInheritanceTest.ChildEntityB.class,
+		AttributeJoinWithRestrictedJoinedInheritanceTest.RootOne.class
+} )
+@SessionFactory
+@Jira( "https://hibernate.atlassian.net/browse/HHH-17646" )
+public class AttributeJoinWithRestrictedJoinedInheritanceTest {
+	@AfterEach
+	public void cleanup(SessionFactoryScope scope) {
+		scope.inTransaction( s -> {
+			s.createMutationQuery( "delete from RootOne" ).executeUpdate();
+			s.createMutationQuery( "delete from SubChildEntityA1" ).executeUpdate();
+			s.createMutationQuery( "delete from SubChildEntityA2" ).executeUpdate();
+			s.createMutationQuery( "delete from BaseClass" ).executeUpdate();
+		} );
+	}
+
+	@Test
+	public void testLeftJoinWithDiscriminatorFiltering(SessionFactoryScope scope) {
+		scope.inTransaction( s -> {
+			final ChildEntityA childEntityA1 = new SubChildEntityA1( 11 );
+			s.persist( childEntityA1 );
+			final ChildEntityA childEntityA2 = new SubChildEntityA2( 21 );
+			s.persist( childEntityA2 );
+			s.persist( new RootOne( 1, childEntityA1 ) );
+			s.persist( new RootOne( 2, childEntityA2 ) );
+		} );
+		scope.inTransaction( s -> {
+			final List<Tuple> resultList = s.createQuery(
+					"select r, ce " +
+							"from RootOne r left join r.child ce " +
+							"order by r.id",
+					Tuple.class
+			).getResultList();
+			assertEquals( 2, resultList.size() );
+			assertResult( resultList.get( 0 ), 1, 11, 11, "child_a_1", SubChildEntityA1.class );
+			assertResult( resultList.get( 1 ), 2, 21, null, null, null );
+		} );
+	}
+
+	private <T extends ChildEntityA> void assertResult(
+			Tuple result,
+			Integer rootId,
+			Integer rootChildId,
+			Integer childId,
+			String discValue,
+			Class<T> subClass) {
+		if ( rootId != null ) {
+			final RootOne root = result.get( 0, RootOne.class );
+			assertEquals( rootId, root.getId() );
+			assertEquals( rootChildId, root.getChildId() );
+		}
+		else {
+			assertNull( result.get( 0 ) );
+		}
+		if ( subClass != null ) {
+			assertInstanceOf( subClass, result.get( 1 ) );
+			final ChildEntityA sub1 = result.get( 1, subClass );
+			assertEquals( childId, sub1.getId() );
+			assertEquals( discValue, sub1.getDiscCol() );
+		}
+		else {
+			assertNull( result.get( 1 ) );
+		}
+	}
+
+	/**
+	 * NOTE: We define a {@link DiscriminatorColumn} to allow multiple subclasses
+	 * to share the same table name. This will need additional care when pruning
+	 * the table expression, since we'll have to add the discriminator condition
+	 * before joining with the subclass tables
+	 */
+	@Entity( name = "BaseClass" )
+	@Inheritance( strategy = InheritanceType.JOINED )
+	@DiscriminatorColumn( name = "disc_col" )
+	@SQLRestriction( "ident < 20" )
+	public static class BaseClass {
+		@Id
+		@Column(name = "ident")
+		private Integer id;
+
+		@Column( name = "disc_col", insertable = false, updatable = false )
+		private String discCol;
+
+		public BaseClass() {
+		}
+
+		public BaseClass(Integer id) {
+			this.id = id;
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public String getDiscCol() {
+			return discCol;
+		}
+	}
+
+	@Entity( name = "ChildEntityA" )
+	@Table( name = "child_entity" )
+	public static abstract class ChildEntityA extends BaseClass {
+
+		public ChildEntityA() {
+		}
+
+		public ChildEntityA(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "SubChildEntityA1" )
+	@DiscriminatorValue( "child_a_1" )
+	public static class SubChildEntityA1 extends ChildEntityA {
+		public SubChildEntityA1() {
+		}
+
+		public SubChildEntityA1(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "SubChildEntityA2" )
+	@DiscriminatorValue( "child_a_2" )
+	public static class SubChildEntityA2 extends ChildEntityA {
+		public SubChildEntityA2() {
+		}
+
+		public SubChildEntityA2(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "ChildEntityB" )
+	@Table( name = "child_entity" )
+	public static class ChildEntityB extends BaseClass {
+
+		public ChildEntityB() {
+		}
+
+		public ChildEntityB(Integer id) {
+			super( id );
+		}
+	}
+
+	@Entity( name = "RootOne" )
+	@Table( name = "root_one" )
+	public static class RootOne {
+		@Id
+		private Integer id;
+
+		@Column( name = "child_id", insertable = false, updatable = false )
+		private Integer childId;
+
+		@ManyToOne
+		@JoinColumn( name = "child_id")
+		private ChildEntityA child;
+
+		public RootOne() {
+		}
+
+		public RootOne(Integer id, ChildEntityA child) {
+			this.id = id;
+			this.child = child;
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public Integer getChildId() {
+			return childId;
+		}
+	}
+}

hibernate-core/src/test/java/org/hibernate/orm/test/join/OuterJoinTest.java

@@ -17,7 +17,6 @@ import org.hibernate.testing.orm.junit.EntityManagerFactoryScope;
 import org.hibernate.testing.orm.junit.Jpa;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -411,7 +410,6 @@ public class OuterJoinTest {
 	}
 
 	@Test
-	@Disabled("Hibernate doesn't support implicit joins")
 	public void testJoinOrderWithRightNormalJoinWithInnerImplicitJoins(EntityManagerFactoryScope scope) {
 		scope.inTransaction( em -> {
 			List<Tuple> resultList = em.createQuery(

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/compliance/LocalTimeTest.java

@@ -35,7 +35,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 )
 public class LocalTimeTest {
 
-	private static final LocalTime LOCAL_TIME = DateTimeUtils.roundToDefaultPrecision(
+	private static final LocalTime LOCAL_TIME = DateTimeUtils.adjustToDefaultPrecision(
 			LocalTime.now(),
 			DialectContext.getDialect()
 	);

hibernate-core/src/test/java/org/hibernate/orm/test/jpa/ql/JoinTableOptimizationTest.java

@@ -8,7 +8,6 @@ package org.hibernate.orm.test.jpa.ql;
 
 import java.util.Set;
 
-import org.hibernate.testing.TestForIssue;
 import org.hibernate.testing.jdbc.SQLStatementInspector;
 import org.hibernate.testing.orm.junit.DomainModel;
 import org.hibernate.testing.orm.junit.JiraKey;
@@ -21,19 +20,28 @@ import jakarta.persistence.CollectionTable;
 import jakarta.persistence.ElementCollection;
 import jakarta.persistence.Embeddable;
 import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
 import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
 import jakarta.persistence.JoinTable;
+import jakarta.persistence.ManyToMany;
+import jakarta.persistence.ManyToOne;
 import jakarta.persistence.OneToMany;
+import jakarta.persistence.Table;
 
-@TestForIssue(jiraKey = "HHH-16691")
 @DomainModel(
 		annotatedClasses = {
-				JoinTableOptimizationTest.Document.class, JoinTableOptimizationTest.Person.class
+				JoinTableOptimizationTest.Document.class,
+				JoinTableOptimizationTest.Person.class,
+				JoinTableOptimizationTest.File.class,
+				JoinTableOptimizationTest.Picture.class
 		})
 @SessionFactory(useCollectingStatementInspector = true)
 public class JoinTableOptimizationTest {
 
 	@Test
+	@JiraKey("HHH-16691")
 	public void testOnlyCollectionTableJoined(SessionFactoryScope scope) {
 		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
 		statementInspector.clear();
@@ -48,6 +56,7 @@ public class JoinTableOptimizationTest {
 	}
 
 	@Test
+	@JiraKey("HHH-16691")
 	public void testInnerJoin(SessionFactoryScope scope) {
 		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
 		statementInspector.clear();
@@ -68,6 +77,7 @@ public class JoinTableOptimizationTest {
 	}
 
 	@Test
+	@JiraKey("HHH-16691")
 	public void testLeftJoin(SessionFactoryScope scope) {
 		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
 		statementInspector.clear();
@@ -88,6 +98,7 @@ public class JoinTableOptimizationTest {
 	}
 
 	@Test
+	@JiraKey("HHH-16691")
 	public void testInnerJoinCustomOnClause(SessionFactoryScope scope) {
 		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
 		statementInspector.clear();
@@ -108,6 +119,7 @@ public class JoinTableOptimizationTest {
 	}
 
 	@Test
+	@JiraKey("HHH-16691")
 	public void testLeftJoinCustomOnClause(SessionFactoryScope scope) {
 		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
 		statementInspector.clear();
@@ -147,6 +159,199 @@ public class JoinTableOptimizationTest {
 		);
 	}
 
+	@Test
+	@JiraKey("HHH-17646")
+	public void testLeftJoinFetch(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select d from Document d left join fetch d.people" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select d1_0.id,d1_0.name,p1_0.Document_id,p1_1.id,p1_1.name " +
+									"from Document d1_0 " +
+									"left join people p1_0 on d1_0.id=p1_0.Document_id " +
+									"left join Person p1_1 on p1_1.id=p1_0.people_id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinTablePolymorphicJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d join d.manyFiles f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select mf1_1.id,case when mf1_2.id is not null then 1 when mf1_1.id is not null then 0 end,mf1_1.document_id,mf1_1.name,mf1_2.extension " +
+									"from Document d1_0 " +
+									"join many_files mf1_0 on d1_0.id=mf1_0.Document_id " +
+									"join file_tbl mf1_1 on mf1_1.id=mf1_0.manyFiles_id " +
+									"left join Picture mf1_2 on mf1_1.id=mf1_2.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinTablePolymorphicLeftJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d left join d.manyFiles f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select mf1_1.id,case when mf1_2.id is not null then 1 when mf1_1.id is not null then 0 end,mf1_1.document_id,mf1_1.name,mf1_2.extension " +
+									"from Document d1_0 " +
+									"left join many_files mf1_0 on d1_0.id=mf1_0.Document_id " +
+									"left join file_tbl mf1_1 on mf1_1.id=mf1_0.manyFiles_id " +
+									"left join Picture mf1_2 on mf1_1.id=mf1_2.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinPolymorphicJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d join d.files f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select f1_0.id,case when f1_1.id is not null then 1 when f1_0.id is not null then 0 end,d1_0.id,d1_0.name,f1_0.name,f1_1.extension " +
+									"from Document d1_0 " +
+									"join file_tbl f1_0 on d1_0.id=f1_0.document_id " +
+									"left join Picture f1_1 on f1_0.id=f1_1.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinPolymorphicLeftJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d left join d.files f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select f1_0.id,case when f1_1.id is not null then 1 when f1_0.id is not null then 0 end,d1_0.id,d1_0.name,f1_0.name,f1_1.extension " +
+									"from Document d1_0 " +
+									"left join file_tbl f1_0 on d1_0.id=f1_0.document_id " +
+									"left join Picture f1_1 on f1_0.id=f1_1.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinTablePolymorphicSubtypeJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d join d.manyPictures f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select mp1_1.id,mp1_2.document_id,mp1_2.name,mp1_1.extension " +
+									"from Document d1_0 " +
+									"join many_pictures mp1_0 on d1_0.id=mp1_0.Document_id " +
+									"join Picture mp1_1 on mp1_1.id=mp1_0.manyPictures_id " +
+									"join file_tbl mp1_2 on mp1_1.id=mp1_2.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinTablePolymorphicSubtypeLeftJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d left join d.manyPictures f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select mp1_1.id,mp1_2.document_id,mp1_2.name,mp1_1.extension " +
+									"from Document d1_0 " +
+									"left join many_pictures mp1_0 on d1_0.id=mp1_0.Document_id " +
+									"left join Picture mp1_1 on mp1_1.id=mp1_0.manyPictures_id " +
+									"left join file_tbl mp1_2 on mp1_1.id=mp1_2.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinPolymorphicSubtypeJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d join d.pictures f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select p1_0.id,p1_1.document_id,p1_1.name,p1_0.extension " +
+									"from Document d1_0 " +
+									"join file_tbl p1_1 on d1_0.id=p1_1.document_id " +
+									"join Picture p1_0 on p1_0.id=p1_1.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
+	@Test
+	@JiraKey("HHH-17646")
+	public void testJoinPolymorphicSubtypeLeftJoined(SessionFactoryScope scope) {
+		SQLStatementInspector statementInspector = scope.getCollectingStatementInspector();
+		statementInspector.clear();
+		scope.inTransaction(
+				s -> {
+					s.createQuery( "select f from Document d left join d.pictures f" ).list();
+					statementInspector.assertExecutedCount( 1 );
+					Assertions.assertEquals(
+							"select p1_0.id,p1_1.document_id,p1_1.name,p1_0.extension " +
+									"from Document d1_0 " +
+									"left join file_tbl p1_1 on d1_0.id=p1_1.document_id " +
+									"left join Picture p1_0 on p1_0.id=p1_1.id",
+							statementInspector.getSqlQueries().get( 0 ),
+							"Nested join was not optimized away"
+					);
+				}
+		);
+	}
+
 	@Entity(name = "Document")
 	public static class Document {
 		@Id
@@ -158,6 +363,16 @@ public class JoinTableOptimizationTest {
 		@ElementCollection
 		@CollectionTable(name = "document_pages")
 		Set<Page> pages;
+		@OneToMany(mappedBy = "document")
+		Set<File> files;
+		@ManyToMany
+		@JoinTable(name = "many_files")
+		Set<File> manyFiles;
+		@OneToMany(mappedBy = "document")
+		Set<Picture> pictures;
+		@ManyToMany
+		@JoinTable(name = "many_pictures")
+		Set<Picture> manyPictures;
 	}
 	@Entity(name = "Person")
 	public static class Person {
@@ -165,6 +380,20 @@ public class JoinTableOptimizationTest {
 		Long id;
 		String name;
 	}
+	@Entity(name = "File")
+	@Table(name = "file_tbl")
+	@Inheritance(strategy = InheritanceType.JOINED)
+	public static class File {
+		@Id
+		Long id;
+		String name;
+		@ManyToOne(fetch = FetchType.LAZY)
+		Document document;
+	}
+	@Entity(name = "Picture")
+	public static class Picture extends File {
+		String extension;
+	}
 	@Embeddable
 	public static class Page {
 		String text;

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/javatime/GlobalJavaTimeJdbcTypeTests.java

@@ -44,7 +44,7 @@ import jakarta.persistence.Id;
 import jakarta.persistence.Table;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.hibernate.type.descriptor.DateTimeUtils.roundToDefaultPrecision;
+import static org.hibernate.type.descriptor.DateTimeUtils.adjustToDefaultPrecision;
 
 /**
  * Tests for "direct" JDBC handling of {@linkplain java.time Java Time} types.
@@ -84,7 +84,7 @@ public class GlobalJavaTimeJdbcTypeTests {
 	@Test
 	void testInstant(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final Instant start = roundToDefaultPrecision( Instant.EPOCH, dialect );
+		final Instant start = adjustToDefaultPrecision( Instant.EPOCH, dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();
@@ -114,7 +114,7 @@ public class GlobalJavaTimeJdbcTypeTests {
 	@Test
 	void testLocalDateTime(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final LocalDateTime start = roundToDefaultPrecision( LocalDateTime.now(), dialect );
+		final LocalDateTime start = adjustToDefaultPrecision( LocalDateTime.now(), dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();
@@ -144,7 +144,7 @@ public class GlobalJavaTimeJdbcTypeTests {
 	@Test
 	void testLocalDate(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final LocalDate startTime = roundToDefaultPrecision( LocalDate.now(), dialect );
+		final LocalDate startTime = adjustToDefaultPrecision( LocalDate.now(), dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();
@@ -177,7 +177,7 @@ public class GlobalJavaTimeJdbcTypeTests {
 	@SkipForDialect(dialectClass = AltibaseDialect.class, reason = "Altibase drivers truncate fractional seconds from the LocalTime")
 	void testLocalTime(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final LocalTime startTime = roundToDefaultPrecision( LocalTime.now(), dialect );
+		final LocalTime startTime = adjustToDefaultPrecision( LocalTime.now(), dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();

hibernate-core/src/test/java/org/hibernate/orm/test/mapping/javatime/JavaTimeJdbcTypeTests.java

@@ -45,7 +45,7 @@ import jakarta.persistence.Id;
 import jakarta.persistence.Table;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.hibernate.type.descriptor.DateTimeUtils.roundToDefaultPrecision;
+import static org.hibernate.type.descriptor.DateTimeUtils.adjustToDefaultPrecision;
 
 /**
  * Tests for "direct" JDBC handling of {@linkplain java.time Java Time} types.
@@ -85,7 +85,7 @@ public class JavaTimeJdbcTypeTests {
 	@Test
 	void testInstant(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final Instant start = roundToDefaultPrecision( Instant.EPOCH, dialect );
+		final Instant start = adjustToDefaultPrecision( Instant.EPOCH, dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();
@@ -115,7 +115,7 @@ public class JavaTimeJdbcTypeTests {
 	@Test
 	void testLocalDateTime(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final LocalDateTime start = roundToDefaultPrecision( LocalDateTime.now(), dialect );
+		final LocalDateTime start = adjustToDefaultPrecision( LocalDateTime.now(), dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();
@@ -145,7 +145,7 @@ public class JavaTimeJdbcTypeTests {
 	@Test
 	void testLocalDate(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final LocalDate startTime = roundToDefaultPrecision( LocalDate.now(), dialect );
+		final LocalDate startTime = adjustToDefaultPrecision( LocalDate.now(), dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();
@@ -178,7 +178,7 @@ public class JavaTimeJdbcTypeTests {
 	@SkipForDialect(dialectClass = AltibaseDialect.class, reason = "Altibase drivers truncate fractional seconds from the LocalTime")
 	void testLocalTime(SessionFactoryScope scope) {
 		final Dialect dialect = scope.getSessionFactory().getJdbcServices().getDialect();
-		final LocalTime startTime = roundToDefaultPrecision( LocalTime.now(), dialect );
+		final LocalTime startTime = adjustToDefaultPrecision( LocalTime.now(), dialect );
 
 		scope.inTransaction( (session) -> {
 			final EntityWithJavaTimeValues entity = new EntityWithJavaTimeValues();

hibernate-core/src/test/java/org/hibernate/orm/test/softdelete/ToOneTests.java

@@ -111,6 +111,23 @@ public class ToOneTests {
 		} );
 	}
 
+	@Test
+	void fkAccessTest(SessionFactoryScope scope) {
+		final SQLStatementInspector sqlInspector = scope.getCollectingStatementInspector();
+		sqlInspector.clear();
+
+		scope.inTransaction( (session) -> {
+			final Integer issue2Reporter = session.createQuery( "select i.reporter.id from Issue i where i.id = 2", Integer.class ).getSingleResultOrNull();
+			assertThat( issue2Reporter ).isNull();
+
+			assertThat( sqlInspector.getSqlQueries() ).hasSize( 1 );
+			assertThat( sqlInspector.getSqlQueries().get( 0 ) ).contains( " join " );
+			assertThat( sqlInspector.getSqlQueries().get( 0 ) ).contains( ".reporter_fk" );
+			assertThat( sqlInspector.getSqlQueries().get( 0 ) ).containsAnyOf( ".active='Y'", ".active=N'Y'" );
+			assertThat( sqlInspector.getSqlQueries().get( 0 ) ).containsOnlyOnce( "active" );
+		} );
+	}
+
 	@Entity(name="Issue")
 	@Table(name="issues")
 	public static class Issue {

hibernate-core/src/test/java/org/hibernate/orm/test/timezones/UTCNormalizedInstantTest.java

@@ -86,10 +86,10 @@ public class UTCNormalizedInstantTest {
 		});
 		scope.inSession( s-> {
 			final Zoned z = s.find(Zoned.class, id);
-				Instant expected = DateTimeUtils.adjustToDefaultPrecision( z.utcInstant, dialect );
+			Instant expected = DateTimeUtils.adjustToDefaultPrecision( z.utcInstant, dialect );
 			Instant actual = DateTimeUtils.adjustToDefaultPrecision( instant, dialect );
 				assertEquals(
-						expected,
+					expected,
 					actual
 			);
 			expected = DateTimeUtils.adjustToDefaultPrecision( z.localInstant, dialect );