HHH-7165 - count() query on classes using EmbeddedId should not use id column tuple on Dialects which dont support non-distinct tuple counts

hibernate-core/src/main/antlr/hql-sql.g

@@ -58,10 +58,14 @@ tokens
     private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, HqlSqlBaseWalker.class.getName());
 
 	private int level = 0;
+
 	private boolean inSelect = false;
 	private boolean inFunctionCall = false;
 	private boolean inCase = false;
 	private boolean inFrom = false;
+	private boolean inCount = false;
+	private boolean inCountDistinct = false;
+
 	private int statementType;
 	private String statementTypeName;
 	// Note: currentClauseType tracks the current clause within the current
@@ -92,6 +96,14 @@ tokens
 		return inCase;
 	}
 
+    public final boolean isInCount() {
+        return inCount;
+    }
+
+    public final boolean isInCountDistinct() {
+        return inCountDistinct;
+    }
+
 	public final int getStatementType() {
 		return statementType;
 	}
@@ -392,7 +404,10 @@ selectExpr
 	;
 
 count
-	: #(COUNT ( DISTINCT | ALL )? ( aggregateExpr | ROW_STAR ) )
+    : #(COUNT  { inCount = true; } ( DISTINCT { inCountDistinct = true; } | ALL )? ( aggregateExpr | ROW_STAR ) ) {
+        inCount = false;
+        inCountDistinct = false;
+    }
     ;
 
 constructor

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/ComponentJoin.java

@@ -41,7 +41,8 @@ public class ComponentJoin extends FromElement {
 	private final ComponentType componentType;
 
 	private final String componentProperty;
-	private final String columns;
+	private final String[] columns;
+	private final String columnsFragment;
 
 	public ComponentJoin(
 			FromClause fromClause,
@@ -56,16 +57,16 @@ public class ComponentJoin extends FromElement {
 		fromClause.addJoinByPathMap( componentPath, this );
 		initializeComponentJoin( new ComponentFromElementType( this ) );
 
-		final String[] cols = origin.getPropertyMapping( "" ).toColumns( getTableAlias(), componentProperty );
+		this.columns = origin.getPropertyMapping( "" ).toColumns( getTableAlias(), componentProperty );
 		StringBuilder buf = new StringBuilder();
-		for ( int j = 0; j < cols.length; j++ ) {
-			final String column = cols[j];
+		for ( int j = 0; j < columns.length; j++ ) {
+			final String column = columns[j];
 			if ( j > 0 ) {
 				buf.append( ", " );
 			}
 			buf.append( column );
 		}
-		this.columns = buf.toString();
+		this.columnsFragment = buf.toString();
 	}
 
 	public String getComponentPath() {
@@ -86,9 +87,6 @@ public class ComponentJoin extends FromElement {
 		return getComponentType();
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
     public String getIdentityColumn() {
 		// used to "resolve" the IdentNode when our alias is encountered *by itself* in the query; so
@@ -96,12 +94,14 @@ public class ComponentJoin extends FromElement {
 		// NOTE : ^^ is true *except for* when encountered by itself in the SELECT clause.  That gets
 		// 		routed through org.hibernate.hql.internal.ast.tree.ComponentJoin.ComponentFromElementType.renderScalarIdentifierSelect()
 		//		which we also override to account for
+		return columnsFragment;
+	}
+
+	@Override
+	public String[] getIdentityColumns() {
 		return columns;
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
     public String getDisplayText() {
 		return "ComponentJoin{path=" + getComponentPath() + ", type=" + componentType.getReturnedClass() + "}";

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/FromElement.java

@@ -325,13 +325,23 @@ public class FromElement extends HqlSqlWalkerNode implements DisplayableNode, Pa
 	}
 
 	public String getIdentityColumn() {
+		final String[] cols = getIdentityColumns();
+		if ( cols.length == 1 ) {
+			return cols[0];
+		}
+		else {
+			return "(" + StringHelper.join( ", ", cols ) + ")";
+		}
+	}
+
+	public String[] getIdentityColumns() {
 		checkInitialized();
-		String table = getTableAlias();
+		final String table = getTableAlias();
 		if ( table == null ) {
 			throw new IllegalStateException( "No table alias for node " + this );
 		}
-		String[] cols;
-		String propertyName;
+
+		final String propertyName;
 		if ( getEntityPersister() != null && getEntityPersister().getEntityMetamodel() != null
 				&& getEntityPersister().getEntityMetamodel().hasNonIdentifierPropertyNamedId() ) {
 			propertyName = getEntityPersister().getIdentifierPropertyName();
@@ -339,14 +349,13 @@ public class FromElement extends HqlSqlWalkerNode implements DisplayableNode, Pa
 		else {
 			propertyName = EntityPersister.ENTITY_ID;
 		}
+
 		if ( getWalker().getStatementType() == HqlSqlTokenTypes.SELECT ) {
-			cols = getPropertyMapping( propertyName ).toColumns( table, propertyName );
+			return getPropertyMapping( propertyName ).toColumns( table, propertyName );
 		}
 		else {
-			cols = getPropertyMapping( propertyName ).toColumns( propertyName );
+			return getPropertyMapping( propertyName ).toColumns( propertyName );
 		}
-		String result = StringHelper.join( ", ", cols );
-		return  cols.length == 1 ? result : "(" + result + ")";
 	}
 
 	public void setCollectionJoin(boolean collectionJoin) {

hibernate-core/src/main/java/org/hibernate/hql/internal/ast/tree/IdentNode.java

@@ -149,11 +149,25 @@ public class IdentNode extends FromReferenceNode implements SelectExpression {
 
 	private boolean resolveAsAlias() {
 		// This is not actually a constant, but a reference to FROM element.
-		FromElement element = getWalker().getCurrentFromClause().getFromElement(getText());
-		if (element != null) {
-			setFromElement(element);
-			setText(element.getIdentityColumn());
-			setType(SqlTokenTypes.ALIAS_REF);
+		FromElement element = getWalker().getCurrentFromClause().getFromElement( getText() );
+		if ( element != null ) {
+			setType( SqlTokenTypes.ALIAS_REF );
+			setFromElement( element );
+			String[] columnExpressions = element.getIdentityColumns();
+			final boolean isInNonDistinctCount = getWalker().isInCount() && ! getWalker().isInCountDistinct();
+			final boolean isCompositePk = columnExpressions.length > 1;
+			if ( isCompositePk
+					&& isInNonDistinctCount
+					&& ! getWalker().getSessionFactoryHelper().getFactory().getDialect().supportsTupleCounts() ) {
+				setText( columnExpressions[0] );
+			}
+			else {
+				String joinedFragment = StringHelper.join( ", ", columnExpressions );
+				if ( ! getWalker().isInCount() ) {
+					joinedFragment = "(" + joinedFragment + ")";
+				}
+				setText( joinedFragment );
+			}
 			return true;
 		}
 		return false;

hibernate-core/src/matrix/java/org/hibernate/test/cid/CompositeIdTest.java

@@ -74,6 +74,27 @@ public class CompositeIdTest extends BaseCoreFunctionalTestCase {
 		assertEquals( expectCommas, hadCommas );
 	}
 
+	@Test
+	public void testDistinctCountOfEntityWithCompositeId() {
+		// today we do not account for Dialects supportsTupleDistinctCounts() is false.  though really the only
+		// "option" there is to throw an error.
+		final HQLQueryPlan plan = sessionFactory().getQueryPlanCache().getHQLQueryPlan(
+				"select count(distinct o) from Order o",
+				false,
+				Collections.EMPTY_MAP
+		);
+		assertEquals( 1, plan.getTranslators().length );
+		final QueryTranslator translator = plan.getTranslators()[0];
+		final String generatedSql = translator.getSQLString();
+		System.out.println( "Generated SQL : " + generatedSql );
+
+		final int countExpressionListStart = generatedSql.indexOf( "count(" );
+		final int countExpressionListEnd = generatedSql.indexOf( ")", countExpressionListStart );
+		final String countExpressionFragment = generatedSql.substring( countExpressionListStart+6, countExpressionListEnd+1 );
+		assertTrue( countExpressionFragment.startsWith( "distinct" ) );
+		assertTrue( countExpressionFragment.contains( "," ) );
+	}
+
 	@Test
 	public void testQuery() {
 		Session s = openSession();