redesign 'collate' and add tests

* and add tests and documentation for 'collate'
* much better and less-ambiguous syntax for collate(), consistent with cast() and treat()
* reimplement collate() using the function infrastructure
* implement collate() for HSQLDB

This feature was previously untested and at least partially broken, and was making a mess 
of the HQL grammar.

documentation/src/main/asciidoc/userguide/chapters/query/hql/QueryLanguage.adoc

@@ -850,6 +850,15 @@ include::{sourcedir}/HQLTest.java[tags=hql-year-function-example]
 ----
 ====
 
+===== `collate()`
+
+Selects a collation to be used for its string-valued argument.
+Collations are useful for <<hql-relational-comparisons,binary comparisons>> with `<` or `>`, and in the <<hql-order-by,order by clause>>.
+
+For example, `collate(p.name as ucs_basic)` specifies the SQL standard collation `ucs_basic`.
+
+IMPORTANT: Collations aren't very portable between databases.
+
 [[hql-function-format]]
 ===== `format()`
 

hibernate-core/src/main/antlr/org/hibernate/grammars/hql/HqlParser.g4

@@ -293,12 +293,12 @@ mapKeyNavigablePath
 // GROUP BY clause
 
 groupByClause
-	:	GROUP BY groupByExpression ( COMMA groupByExpression )*
+	: GROUP BY groupByExpression ( COMMA groupByExpression )*
 	;
 
 groupByExpression
-	: identifier collationSpecification?
+	: identifier
-	| INTEGER_LITERAL collationSpecification?
+	| INTEGER_LITERAL
 	| expression
 	;
 
@@ -306,7 +306,7 @@ groupByExpression
 //HAVING clause
 
 havingClause
-	:	HAVING predicate
+	: HAVING predicate
 	;
 
 
@@ -333,22 +333,22 @@ nullsPrecedence
 	;
 
 sortExpression
-	: identifier collationSpecification?
+	: identifier
-	| INTEGER_LITERAL collationSpecification?
+	| INTEGER_LITERAL
 	| expression
 	;
 
-collationSpecification
+collationExpression
-	:	COLLATE collateName
+	: COLLATE LEFT_PAREN expression AS collation RIGHT_PAREN
 	;
 
-collateName
+collation
-	:	dotIdentifierSequence
+	: dotIdentifierSequence
 	;
 
 orderingSpecification
-	:	ASC
+	: ASC
-	|	DESC
+	| DESC
 	;
 
 
@@ -384,7 +384,7 @@ parameterOrNumberLiteral
 // WHERE clause & Predicates
 
 whereClause
-	:	WHERE predicate
+	: WHERE predicate
 	;
 
 predicate
@@ -436,7 +436,7 @@ expression
 	: LEFT_PAREN expression RIGHT_PAREN												# GroupedExpression
 	| LEFT_PAREN expressionOrPredicate (COMMA expressionOrPredicate)+ RIGHT_PAREN	# TupleExpression
 	| LEFT_PAREN subquery RIGHT_PAREN												# SubqueryExpression
-	| primaryExpression collationSpecification?										# CollateExpression
+	| primaryExpression 															# BarePrimaryExpression
 	| signOperator numericLiteral													# UnaryNumericLiteralExpression
 	| signOperator expression														# UnaryExpression
 	| expression datetimeField  													# ToDurationExpression
@@ -707,6 +707,7 @@ standardFunction
 	|	offsetDateTimeFunction
 	|	cube
 	|	rollup
+	|	collationExpression
 	;
 
 

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

@@ -792,6 +792,7 @@ public abstract class Dialect implements ConversionContext {
 	 *
 	 * <ul>
 	 * <li> format(datetime as pattern)
+	 * <li> collate(string as collation)
 	 * <li> str(arg)					- synonym of cast(a as String)
 	 * <li> ifnull(arg0, arg1)			- synonym of coalesce(a, b)
 	 * </ul>
@@ -897,6 +898,10 @@ public abstract class Dialect implements ConversionContext {
 				)
 		);
 
+		//There is a 'collate' operator in a number of major databases
+
+		CommonFunctionFactory.collate( queryEngine );
+
 		//ANSI SQL extract() function is supported on the databases we care most
 		//about (though it is called datepart() in some of them) but HQL defines
 		//additional non-standard temporal field types, which must be emulated in

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

@@ -210,6 +210,7 @@ public class HSQLDialect extends Dialect {
 		CommonFunctionFactory.varPopSamp( queryEngine );
 		CommonFunctionFactory.addMonths( queryEngine );
 		CommonFunctionFactory.monthsBetween( queryEngine );
+		CommonFunctionFactory.collate_quoted( queryEngine );
 
 		if ( getVersion().isSameOrAfter( 2 ) ) {
 			//SYSDATE is similar to LOCALTIMESTAMP but it returns the timestamp when it is called

hibernate-core/src/main/java/org/hibernate/dialect/function/CommonFunctionFactory.java

@@ -2185,6 +2185,32 @@ public class CommonFunctionFactory {
 				.register();
 	}
 
+	/**
+	 * Use the 'collate' operator which exists on at least Postgres, MySQL, Oracle, and SQL Server
+	 */
+	public static void collate(QueryEngine queryEngine) {
+		queryEngine.getSqmFunctionRegistry().patternDescriptorBuilder("collate", "(?1 collate ?2)")
+				.setInvariantType(
+						queryEngine.getTypeConfiguration().getBasicTypeRegistry().resolve( StandardBasicTypes.STRING )
+				)
+				.setExactArgumentCount( 2 )
+				.setArgumentListSignature("(string as collation)")
+				.register();
+	}
+
+	/**
+	 * HSQL requires quotes around certain collations
+	 */
+	public static void collate_quoted(QueryEngine queryEngine) {
+		queryEngine.getSqmFunctionRegistry().patternDescriptorBuilder("collate", "(?1 collate '?2')")
+				.setInvariantType(
+						queryEngine.getTypeConfiguration().getBasicTypeRegistry().resolve( StandardBasicTypes.STRING )
+				)
+				.setExactArgumentCount( 2 )
+				.setArgumentListSignature("(string as collation)")
+				.register();
+	}
+
 	public static void dateTrunc(QueryEngine queryEngine) {
 		queryEngine.getSqmFunctionRegistry().patternDescriptorBuilder( "date_trunc", "date_trunc('?1',?2)" )
 				.setInvariantType(

hibernate-core/src/main/java/org/hibernate/query/hql/internal/SemanticQueryBuilder.java

@@ -114,7 +114,7 @@ import org.hibernate.query.sqm.tree.expression.SqmByUnit;
 import org.hibernate.query.sqm.tree.expression.SqmCaseSearched;
 import org.hibernate.query.sqm.tree.expression.SqmCaseSimple;
 import org.hibernate.query.sqm.tree.expression.SqmCastTarget;
-import org.hibernate.query.sqm.tree.expression.SqmCollate;
+import org.hibernate.query.sqm.tree.expression.SqmCollation;
 import org.hibernate.query.sqm.tree.expression.SqmCollectionSize;
 import org.hibernate.query.sqm.tree.expression.SqmDistinct;
 import org.hibernate.query.sqm.tree.expression.SqmDurationUnit;
@@ -1912,7 +1912,7 @@ public class SemanticQueryBuilder<R> extends HqlParserBaseVisitor<Object> implem
 	private Map<Class<?>, Enum<?>> getPossibleEnumValues(HqlParser.ExpressionContext expressionContext) {
 		ParseTree ctx;
 		// Traverse the expression structure according to the grammar
-		if ( expressionContext instanceof HqlParser.CollateExpressionContext && expressionContext.getChildCount() == 1 ) {
+		if ( expressionContext instanceof HqlParser.BarePrimaryExpressionContext && expressionContext.getChildCount() == 1 ) {
 			ctx = expressionContext.getChild( 0 );
 
 			while ( ctx instanceof HqlParser.PrimaryExpressionContext && ctx.getChildCount() == 1 ) {
@@ -2326,17 +2326,30 @@ public class SemanticQueryBuilder<R> extends HqlParserBaseVisitor<Object> implem
 	}
 
 	@Override
-	public Object visitCollateExpression(HqlParser.CollateExpressionContext ctx) {
+	public Object visitCollationExpression(HqlParser.CollationExpressionContext ctx) {
-		SqmExpression<?> expression = (SqmExpression<?>) ctx.getChild( 0 ).accept( this );
-		if ( ctx.getChildCount() == 1 ) {
-			return expression;
-		}
 		if ( creationOptions.useStrictJpaCompliance() ) {
 			throw new StrictJpaComplianceViolation(
 					StrictJpaComplianceViolation.Type.COLLATIONS
 			);
 		}
-		return new SqmCollate<>( expression, ctx.getChild( 1 ).getChild( 1 ).getText() );
+
+		final SqmExpression<?> expressionToCollate = (SqmExpression<?>) ctx.getChild( 2 ).accept( this );
+		final SqmCollation castTargetExpression = (SqmCollation) ctx.getChild( 4 ).accept( this );
+
+		return getFunctionDescriptor("collate").generateSqmExpression(
+				asList( expressionToCollate, castTargetExpression ),
+				null, //why not string?
+				creationContext.getQueryEngine(),
+				creationContext.getJpaMetamodel().getTypeConfiguration()
+		);
+	}
+
+	@Override
+	public Object visitCollation(HqlParser.CollationContext ctx) {
+		return new SqmCollation(
+				ctx.getChild( 0 ).getText(),
+				null,
+				creationContext.getNodeBuilder() );
 	}
 
 	@Override
@@ -3466,7 +3479,7 @@ public class SemanticQueryBuilder<R> extends HqlParserBaseVisitor<Object> implem
 
 		return getFunctionDescriptor("format").generateSqmExpression(
 				asList( expressionToCast, format ),
-				null,
+				null, //why not string?
 				creationContext.getQueryEngine(),
 				creationContext.getJpaMetamodel().getTypeConfiguration()
 		);

hibernate-core/src/main/java/org/hibernate/query/sqm/SemanticQueryWalker.java

@@ -27,6 +27,7 @@ import org.hibernate.query.sqm.tree.domain.SqmMinIndexPath;
 import org.hibernate.query.sqm.tree.domain.SqmPluralPartJoin;
 import org.hibernate.query.sqm.tree.domain.SqmPluralValuedSimplePath;
 import org.hibernate.query.sqm.tree.domain.SqmTreatedPath;
+import org.hibernate.query.sqm.tree.expression.JpaCriteriaParameter;
 import org.hibernate.query.sqm.tree.expression.SqmAny;
 import org.hibernate.query.sqm.tree.expression.SqmBinaryArithmetic;
 import org.hibernate.query.sqm.tree.expression.SqmByUnit;
@@ -34,30 +35,29 @@ import org.hibernate.query.sqm.tree.expression.SqmCaseSearched;
 import org.hibernate.query.sqm.tree.expression.SqmCaseSimple;
 import org.hibernate.query.sqm.tree.expression.SqmCastTarget;
 import org.hibernate.query.sqm.tree.expression.SqmCoalesce;
-import org.hibernate.query.sqm.tree.expression.SqmCollate;
+import org.hibernate.query.sqm.tree.expression.SqmCollation;
 import org.hibernate.query.sqm.tree.expression.SqmCollectionSize;
-import org.hibernate.query.sqm.tree.expression.JpaCriteriaParameter;
+import org.hibernate.query.sqm.tree.expression.SqmDistinct;
 import org.hibernate.query.sqm.tree.expression.SqmDurationUnit;
+import org.hibernate.query.sqm.tree.expression.SqmEnumLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmEvery;
+import org.hibernate.query.sqm.tree.expression.SqmExpression;
+import org.hibernate.query.sqm.tree.expression.SqmExtractUnit;
+import org.hibernate.query.sqm.tree.expression.SqmFieldLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmFormat;
 import org.hibernate.query.sqm.tree.expression.SqmFunction;
-import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
-import org.hibernate.query.sqm.tree.expression.SqmParameterizedEntityType;
-import org.hibernate.query.sqm.tree.expression.SqmEnumLiteral;
-import org.hibernate.query.sqm.tree.expression.SqmExpression;
-import org.hibernate.query.sqm.tree.expression.SqmFieldLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmLiteralEntityType;
+import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
 import org.hibernate.query.sqm.tree.expression.SqmNamedParameter;
+import org.hibernate.query.sqm.tree.expression.SqmParameterizedEntityType;
 import org.hibernate.query.sqm.tree.expression.SqmPositionalParameter;
+import org.hibernate.query.sqm.tree.expression.SqmStar;
 import org.hibernate.query.sqm.tree.expression.SqmSummarization;
 import org.hibernate.query.sqm.tree.expression.SqmToDuration;
+import org.hibernate.query.sqm.tree.expression.SqmTrimSpecification;
 import org.hibernate.query.sqm.tree.expression.SqmTuple;
 import org.hibernate.query.sqm.tree.expression.SqmUnaryOperation;
-import org.hibernate.query.sqm.tree.expression.SqmDistinct;
-import org.hibernate.query.sqm.tree.expression.SqmExtractUnit;
-import org.hibernate.query.sqm.tree.expression.SqmStar;
-import org.hibernate.query.sqm.tree.expression.SqmTrimSpecification;
 import org.hibernate.query.sqm.tree.from.SqmAttributeJoin;
 import org.hibernate.query.sqm.tree.from.SqmCrossJoin;
 import org.hibernate.query.sqm.tree.from.SqmEntityJoin;
@@ -197,7 +197,7 @@ public interface SemanticQueryWalker<T> {
 
 	T visitTuple(SqmTuple<?> sqmTuple);
 
-	T visitCollate(SqmCollate<?> sqmCollate);
+	T visitCollation(SqmCollation sqmCollate);
 
 	T visitBinaryArithmeticExpression(SqmBinaryArithmetic<?> expression);
 

hibernate-core/src/main/java/org/hibernate/query/sqm/function/SqmFunctionRegistry.java

@@ -107,7 +107,7 @@ public class SqmFunctionRegistry {
 	 * Get a builder for creating and registering a pattern-based function descriptor.
 	 *
 	 * @param registrationKey The name under which the descriptor will get registered
-	 * @param pattern The pattern defining the the underlying function call
+	 * @param pattern The pattern defining the underlying function call
 	 *
 	 * @return The builder
 	 */
@@ -119,7 +119,7 @@ public class SqmFunctionRegistry {
 	 * Get a builder for creating and registering a pattern-based aggregate function descriptor.
 	 *
 	 * @param registrationKey The name under which the descriptor will get registered
-	 * @param pattern The pattern defining the the underlying function call
+	 * @param pattern The pattern defining the underlying function call
 	 *
 	 * @return The builder
 	 */

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

@@ -40,7 +40,7 @@ import org.hibernate.query.sqm.tree.expression.SqmCaseSearched;
 import org.hibernate.query.sqm.tree.expression.SqmCaseSimple;
 import org.hibernate.query.sqm.tree.expression.SqmCastTarget;
 import org.hibernate.query.sqm.tree.expression.SqmCoalesce;
-import org.hibernate.query.sqm.tree.expression.SqmCollate;
+import org.hibernate.query.sqm.tree.expression.SqmCollation;
 import org.hibernate.query.sqm.tree.expression.SqmCollectionSize;
 import org.hibernate.query.sqm.tree.expression.SqmDistinct;
 import org.hibernate.query.sqm.tree.expression.SqmDurationUnit;
@@ -53,10 +53,10 @@ import org.hibernate.query.sqm.tree.expression.SqmFormat;
 import org.hibernate.query.sqm.tree.expression.SqmFunction;
 import org.hibernate.query.sqm.tree.expression.SqmLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmLiteralEntityType;
+import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
 import org.hibernate.query.sqm.tree.expression.SqmNamedParameter;
 import org.hibernate.query.sqm.tree.expression.SqmParameterizedEntityType;
 import org.hibernate.query.sqm.tree.expression.SqmPositionalParameter;
-import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
 import org.hibernate.query.sqm.tree.expression.SqmStar;
 import org.hibernate.query.sqm.tree.expression.SqmSummarization;
 import org.hibernate.query.sqm.tree.expression.SqmToDuration;
@@ -977,7 +977,7 @@ public class SqmTreePrinter implements SemanticQueryWalker<Object> {
 	}
 
 	@Override
-	public Object visitCollate(SqmCollate<?> sqmCollate) {
+	public Object visitCollation(SqmCollation sqmCollate) {
 		return null;
 	}
 

hibernate-core/src/main/java/org/hibernate/query/sqm/mutation/internal/cte/CteInsertHandler.java

@@ -829,7 +829,6 @@ public class CteInsertHandler implements InsertHandler {
 				insertSelectSpec.addSortSpecification(
 						new SortSpecification(
 								rowNumberColumnReference,
-								null,
 								SortOrder.ASCENDING
 						)
 				);
@@ -996,7 +995,6 @@ public class CteInsertHandler implements InsertHandler {
 				finalResultQuery.addSortSpecification(
 						new SortSpecification(
 								idColumnReference,
-								null,
 								SortOrder.ASCENDING
 						)
 				);

hibernate-core/src/main/java/org/hibernate/query/sqm/mutation/internal/temptable/InsertExecutionDelegate.java

@@ -317,7 +317,6 @@ public class InsertExecutionDelegate implements TableBasedInsertHandler.Executio
 			idSelectQuerySpec.addSortSpecification(
 					new SortSpecification(
 							columnReference,
-							null,
 							SortOrder.ASCENDING
 					)
 			);

hibernate-core/src/main/java/org/hibernate/query/sqm/spi/BaseSemanticQueryWalker.java

@@ -40,29 +40,29 @@ import org.hibernate.query.sqm.tree.expression.SqmCaseSearched;
 import org.hibernate.query.sqm.tree.expression.SqmCaseSimple;
 import org.hibernate.query.sqm.tree.expression.SqmCastTarget;
 import org.hibernate.query.sqm.tree.expression.SqmCoalesce;
-import org.hibernate.query.sqm.tree.expression.SqmCollate;
+import org.hibernate.query.sqm.tree.expression.SqmCollation;
 import org.hibernate.query.sqm.tree.expression.SqmCollectionSize;
+import org.hibernate.query.sqm.tree.expression.SqmDistinct;
 import org.hibernate.query.sqm.tree.expression.SqmDurationUnit;
 import org.hibernate.query.sqm.tree.expression.SqmEnumLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmEvery;
 import org.hibernate.query.sqm.tree.expression.SqmExpression;
+import org.hibernate.query.sqm.tree.expression.SqmExtractUnit;
 import org.hibernate.query.sqm.tree.expression.SqmFieldLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmFormat;
 import org.hibernate.query.sqm.tree.expression.SqmFunction;
 import org.hibernate.query.sqm.tree.expression.SqmLiteral;
 import org.hibernate.query.sqm.tree.expression.SqmLiteralEntityType;
+import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
 import org.hibernate.query.sqm.tree.expression.SqmNamedParameter;
 import org.hibernate.query.sqm.tree.expression.SqmParameterizedEntityType;
 import org.hibernate.query.sqm.tree.expression.SqmPositionalParameter;
-import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
+import org.hibernate.query.sqm.tree.expression.SqmStar;
 import org.hibernate.query.sqm.tree.expression.SqmSummarization;
 import org.hibernate.query.sqm.tree.expression.SqmToDuration;
+import org.hibernate.query.sqm.tree.expression.SqmTrimSpecification;
 import org.hibernate.query.sqm.tree.expression.SqmTuple;
 import org.hibernate.query.sqm.tree.expression.SqmUnaryOperation;
-import org.hibernate.query.sqm.tree.expression.SqmDistinct;
-import org.hibernate.query.sqm.tree.expression.SqmExtractUnit;
-import org.hibernate.query.sqm.tree.expression.SqmStar;
-import org.hibernate.query.sqm.tree.expression.SqmTrimSpecification;
 import org.hibernate.query.sqm.tree.from.SqmAttributeJoin;
 import org.hibernate.query.sqm.tree.from.SqmCrossJoin;
 import org.hibernate.query.sqm.tree.from.SqmEntityJoin;
@@ -676,8 +676,7 @@ public abstract class BaseSemanticQueryWalker implements SemanticQueryWalker<Obj
 	}
 
 	@Override
-	public Object visitCollate(SqmCollate<?> sqmCollate) {
+	public Object visitCollation(SqmCollation sqmCollate) {
-		sqmCollate.getExpression().accept( this );
 		return sqmCollate;
 	}
 

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

@@ -101,7 +101,7 @@ import org.hibernate.query.sqm.tree.SqmJoinType;
 import org.hibernate.query.sqm.tree.domain.SqmCorrelatedRootJoin;
 import org.hibernate.query.sqm.tree.domain.SqmCorrelation;
 import org.hibernate.query.sqm.tree.domain.SqmPluralPartJoin;
-import org.hibernate.query.sqm.tree.expression.SqmModifiedSubQueryExpression;
+import org.hibernate.query.sqm.tree.expression.*;
 import org.hibernate.query.sqm.tree.insert.SqmInsertStatement;
 import org.hibernate.sql.ast.tree.expression.ModifiedSubQueryExpression;
 import org.hibernate.query.sqm.tree.domain.SqmTreatedRoot;
@@ -175,40 +175,6 @@ import org.hibernate.query.sqm.tree.domain.SqmMinIndexPath;
 import org.hibernate.query.sqm.tree.domain.SqmPath;
 import org.hibernate.query.sqm.tree.domain.SqmPluralValuedSimplePath;
 import org.hibernate.query.sqm.tree.domain.SqmTreatedPath;
-import org.hibernate.query.sqm.tree.expression.Conversion;
-import org.hibernate.query.sqm.tree.expression.JpaCriteriaParameter;
-import org.hibernate.query.sqm.tree.expression.SqmAliasedNodeRef;
-import org.hibernate.query.sqm.tree.expression.SqmAny;
-import org.hibernate.query.sqm.tree.expression.SqmBinaryArithmetic;
-import org.hibernate.query.sqm.tree.expression.SqmByUnit;
-import org.hibernate.query.sqm.tree.expression.SqmCaseSearched;
-import org.hibernate.query.sqm.tree.expression.SqmCaseSimple;
-import org.hibernate.query.sqm.tree.expression.SqmCastTarget;
-import org.hibernate.query.sqm.tree.expression.SqmCollate;
-import org.hibernate.query.sqm.tree.expression.SqmCollectionSize;
-import org.hibernate.query.sqm.tree.expression.SqmDistinct;
-import org.hibernate.query.sqm.tree.expression.SqmDurationUnit;
-import org.hibernate.query.sqm.tree.expression.SqmEnumLiteral;
-import org.hibernate.query.sqm.tree.expression.SqmEvery;
-import org.hibernate.query.sqm.tree.expression.SqmExpression;
-import org.hibernate.query.sqm.tree.expression.SqmExtractUnit;
-import org.hibernate.query.sqm.tree.expression.SqmFieldLiteral;
-import org.hibernate.query.sqm.tree.expression.SqmFormat;
-import org.hibernate.query.sqm.tree.expression.SqmFunction;
-import org.hibernate.query.sqm.tree.expression.SqmJpaCriteriaParameterWrapper;
-import org.hibernate.query.sqm.tree.expression.SqmLiteral;
-import org.hibernate.query.sqm.tree.expression.SqmLiteralEntityType;
-import org.hibernate.query.sqm.tree.expression.SqmLiteralNull;
-import org.hibernate.query.sqm.tree.expression.SqmNamedParameter;
-import org.hibernate.query.sqm.tree.expression.SqmParameter;
-import org.hibernate.query.sqm.tree.expression.SqmParameterizedEntityType;
-import org.hibernate.query.sqm.tree.expression.SqmPositionalParameter;
-import org.hibernate.query.sqm.tree.expression.SqmStar;
-import org.hibernate.query.sqm.tree.expression.SqmSummarization;
-import org.hibernate.query.sqm.tree.expression.SqmToDuration;
-import org.hibernate.query.sqm.tree.expression.SqmTrimSpecification;
-import org.hibernate.query.sqm.tree.expression.SqmTuple;
-import org.hibernate.query.sqm.tree.expression.SqmUnaryOperation;
 import org.hibernate.query.sqm.tree.from.SqmAttributeJoin;
 import org.hibernate.query.sqm.tree.from.SqmCrossJoin;
 import org.hibernate.query.sqm.tree.from.SqmEntityJoin;
@@ -281,7 +247,7 @@ 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.CastTarget;
-import org.hibernate.sql.ast.tree.expression.Collate;
+import org.hibernate.sql.ast.tree.expression.Collation;
 import org.hibernate.sql.ast.tree.expression.ColumnReference;
 import org.hibernate.sql.ast.tree.expression.Distinct;
 import org.hibernate.sql.ast.tree.expression.Duration;
@@ -3707,7 +3673,6 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 							subQuerySpec.addSortSpecification(
 									new SortSpecification(
 											columnReference,
-											null,
 											max ? SortOrder.DESCENDING : SortOrder.ASCENDING
 									)
 							);
@@ -4559,11 +4524,8 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 	}
 
 	@Override
-	public Object visitCollate(SqmCollate<?> sqmCollate) {
+	public Object visitCollation(SqmCollation sqmCollation) {
-		return new Collate(
+		return new Collation( sqmCollation.getLiteralValue() );
-				(Expression) sqmCollate.getExpression().accept( this ),
-				sqmCollate.getCollation()
-		);
 	}
 
 	@Override
@@ -4628,10 +4590,7 @@ public abstract class BaseSqmToSqlAstConverter<T extends Statement> extends Base
 
 	@Override
 	public Object visitFormat(SqmFormat sqmFormat) {
-		return new Format(
+		return new Format( sqmFormat.getLiteralValue() );
-				sqmFormat.getLiteralValue(),
-				(BasicValuedMapping) sqmFormat.getNodeType()
-		);
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/query/sqm/tree/expression/SqmCollate.java

@@ -1,45 +0,0 @@
-/*
- * 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.query.sqm.tree.expression;
-
-import org.hibernate.query.sqm.SemanticQueryWalker;
-
-/**
- * @author Christian Beikov
- */
-public class SqmCollate<T> extends AbstractSqmExpression<T> {
-
-	private final SqmExpression<T> expression;
-	private final String collation;
-
-	public SqmCollate(SqmExpression<T> expression, String collation) {
-		super( expression.getNodeType(), expression.nodeBuilder() );
-		assert !(expression instanceof SqmTuple);
-		this.expression = expression;
-		this.collation = collation;
-	}
-
-	public SqmExpression<T> getExpression() {
-		return expression;
-	}
-
-	public String getCollation() {
-		return collation;
-	}
-
-	@Override
-	public <X> X accept(SemanticQueryWalker<X> walker) {
-		return walker.visitCollate( this );
-	}
-
-	@Override
-	public void appendHqlString(StringBuilder sb) {
-		expression.appendHqlString( sb );
-		sb.append( " collate " );
-		sb.append( collation );
-	}
-}

hibernate-core/src/main/java/org/hibernate/query/sqm/tree/expression/SqmCollation.java

@@ -0,0 +1,30 @@
+/*
+ * 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.query.sqm.tree.expression;
+
+import org.hibernate.query.sqm.NodeBuilder;
+import org.hibernate.query.sqm.SemanticQueryWalker;
+import org.hibernate.query.sqm.SqmExpressable;
+
+/**
+ * @author Christian Beikov
+ */
+public class SqmCollation extends SqmLiteral<String> {
+	public SqmCollation(String value, SqmExpressable<String> inherentType, NodeBuilder nodeBuilder) {
+		super(value, inherentType, nodeBuilder);
+	}
+
+	@Override
+	public <R> R accept(SemanticQueryWalker<R> walker) {
+		return walker.visitCollation( this );
+	}
+
+	@Override
+	public void appendHqlString(StringBuilder sb) {
+		sb.append( getLiteralValue() );
+	}
+}

hibernate-core/src/main/java/org/hibernate/sql/ast/SqlAstWalker.java

@@ -16,7 +16,7 @@ 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.CastTarget;
-import org.hibernate.sql.ast.tree.expression.Collate;
+import org.hibernate.sql.ast.tree.expression.Collation;
 import org.hibernate.sql.ast.tree.expression.ColumnReference;
 import org.hibernate.sql.ast.tree.expression.Distinct;
 import org.hibernate.sql.ast.tree.expression.Duration;
@@ -149,7 +149,7 @@ public interface SqlAstWalker {
 
 	void visitTuple(SqlTuple tuple);
 
-	void visitCollate(Collate collate);
+	void visitCollation(Collation collation);
 
 	void visitParameter(JdbcParameter jdbcParameter);
 

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

@@ -85,7 +85,7 @@ 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.CastTarget;
-import org.hibernate.sql.ast.tree.expression.Collate;
+import org.hibernate.sql.ast.tree.expression.Collation;
 import org.hibernate.sql.ast.tree.expression.ColumnReference;
 import org.hibernate.sql.ast.tree.expression.Distinct;
 import org.hibernate.sql.ast.tree.expression.Duration;
@@ -4335,10 +4335,8 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 	}
 
 	@Override
-	public void visitCollate(Collate collate) {
+	public void visitCollation(Collation collation) {
-		collate.getExpression().accept( this );
+		appendSql( collation.getCollation() );
-		appendSql( " collate " );
-		appendSql( collate.getCollation() );
 	}
 
 	@Override

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

@@ -19,7 +19,7 @@ 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.CastTarget;
-import org.hibernate.sql.ast.tree.expression.Collate;
+import org.hibernate.sql.ast.tree.expression.Collation;
 import org.hibernate.sql.ast.tree.expression.ColumnReference;
 import org.hibernate.sql.ast.tree.expression.Distinct;
 import org.hibernate.sql.ast.tree.expression.Duration;
@@ -162,8 +162,7 @@ public class AbstractSqlAstWalker implements SqlAstWalker {
 	}
 
 	@Override
-	public void visitCollate(Collate collate) {
+	public void visitCollation(Collation collation) {
-		collate.getExpression().accept( this );
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/expression/Collate.java

@@ -1,106 +0,0 @@
-/*
- * 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.tree.expression;
-
-import org.hibernate.mapping.IndexedConsumer;
-import org.hibernate.metamodel.mapping.JdbcMapping;
-import org.hibernate.metamodel.mapping.JdbcMappingContainer;
-import org.hibernate.metamodel.mapping.SqlExpressable;
-import org.hibernate.query.sqm.sql.internal.DomainResultProducer;
-import org.hibernate.sql.ast.SqlAstWalker;
-import org.hibernate.sql.ast.spi.SqlAstCreationState;
-import org.hibernate.sql.ast.spi.SqlExpressionResolver;
-import org.hibernate.sql.ast.tree.SqlAstNode;
-import org.hibernate.sql.results.graph.DomainResult;
-import org.hibernate.sql.results.graph.DomainResultCreationState;
-import org.hibernate.sql.results.graph.basic.BasicResult;
-import org.hibernate.type.descriptor.java.JavaType;
-
-/**
- * @author Christian Beikov
- */
-public class Collate implements Expression, SqlExpressable, SqlAstNode, DomainResultProducer {
-
-	private final Expression expression;
-	private final String collation;
-
-	public Collate(Expression expression, String collation) {
-		this.expression = expression;
-		this.collation = collation;
-	}
-
-	public Expression getExpression() {
-		return expression;
-	}
-
-	public String getCollation() {
-		return collation;
-	}
-
-	@Override
-	public JdbcMapping getJdbcMapping() {
-		if ( expression instanceof SqlExpressable ) {
-			return ( (SqlExpressable) expression ).getJdbcMapping();
-		}
-
-		if ( getExpressionType() instanceof SqlExpressable ) {
-			return ( (SqlExpressable) getExpressionType() ).getJdbcMapping();
-		}
-
-		if ( getExpressionType() != null ) {
-			final JdbcMappingContainer mappingContainer = getExpressionType();
-			assert mappingContainer.getJdbcTypeCount() == 1;
-			return mappingContainer.getJdbcMappings().get( 0 );
-		}
-
-		return null;
-	}
-
-	@Override
-	public JdbcMappingContainer getExpressionType() {
-		return expression.getExpressionType();
-	}
-
-	@Override
-	public void accept(SqlAstWalker sqlTreeWalker) {
-		sqlTreeWalker.visitCollate( this );
-	}
-
-	@Override
-	public DomainResult createDomainResult(
-			String resultVariable,
-			DomainResultCreationState creationState) {
-		final JavaType javaTypeDescriptor = expression.getExpressionType().getJdbcMappings().get( 0 ).getJavaTypeDescriptor();
-		return new BasicResult(
-				creationState.getSqlAstCreationState().getSqlExpressionResolver().resolveSqlSelection(
-						this,
-						javaTypeDescriptor,
-						creationState.getSqlAstCreationState().getCreationContext().getDomainModel().getTypeConfiguration()
-				).getValuesArrayPosition(),
-				resultVariable,
-				javaTypeDescriptor
-		);
-	}
-
-	@Override
-	public void applySqlSelections(DomainResultCreationState creationState) {
-		final SqlAstCreationState sqlAstCreationState = creationState.getSqlAstCreationState();
-		final SqlExpressionResolver sqlExpressionResolver = sqlAstCreationState.getSqlExpressionResolver();
-
-		sqlExpressionResolver.resolveSqlSelection(
-				this,
-				expression.getExpressionType().getJdbcMappings().get( 0 ).getJavaTypeDescriptor(),
-				sqlAstCreationState.getCreationContext().getDomainModel().getTypeConfiguration()
-		);
-	}
-
-	@Override
-	public int forEachJdbcType(int offset, IndexedConsumer<JdbcMapping> action) {
-		action.accept( offset, getJdbcMapping() );
-		return getJdbcTypeCount();
-	}
-}

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/expression/Collation.java

@@ -0,0 +1,44 @@
+/*
+ * 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.tree.expression;
+
+import org.hibernate.mapping.IndexedConsumer;
+import org.hibernate.metamodel.mapping.JdbcMapping;
+import org.hibernate.metamodel.mapping.SqlExpressable;
+import org.hibernate.sql.ast.SqlAstWalker;
+import org.hibernate.sql.ast.tree.SqlAstNode;
+
+/**
+ * @author Christian Beikov
+ */
+public class Collation implements SqlExpressable, SqlAstNode {
+
+	private final String collation;
+
+	public Collation(String collation) {
+		this.collation = collation;
+	}
+
+	public String getCollation() {
+		return collation;
+	}
+
+	@Override
+	public void accept(SqlAstWalker walker) {
+		walker.visitCollation( this );
+	}
+
+	@Override
+	public int forEachJdbcType(int offset, IndexedConsumer<JdbcMapping> action) {
+		return getJdbcTypeCount();
+	}
+
+	@Override
+	public JdbcMapping getJdbcMapping() {
+		return null;
+	}
+}

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/expression/Format.java

@@ -7,7 +7,6 @@
 package org.hibernate.sql.ast.tree.expression;
 
 import org.hibernate.mapping.IndexedConsumer;
-import org.hibernate.metamodel.mapping.BasicValuedMapping;
 import org.hibernate.metamodel.mapping.JdbcMapping;
 import org.hibernate.metamodel.mapping.SqlExpressable;
 import org.hibernate.sql.ast.SqlAstWalker;
@@ -20,11 +19,9 @@ import org.hibernate.sql.ast.tree.SqlAstNode;
  */
 public class Format implements SqlExpressable, SqlAstNode {
 	private String format;
-	private BasicValuedMapping type;
 
-	public Format(String format, BasicValuedMapping type) {
+	public Format(String format) {
 		this.format = format;
-		this.type = type;
 	}
 
 	public String getFormat() {
@@ -33,7 +30,7 @@ public class Format implements SqlExpressable, SqlAstNode {
 
 	@Override
 	public JdbcMapping getJdbcMapping() {
-		return type.getJdbcMapping();
+		return null;
 	}
 
 	@Override
@@ -43,7 +40,6 @@ public class Format implements SqlExpressable, SqlAstNode {
 
 	@Override
 	public int forEachJdbcType(int offset, IndexedConsumer<JdbcMapping> action) {
-		action.accept( offset, type.getJdbcMapping() );
 		return getJdbcTypeCount();
 	}
 }

hibernate-core/src/main/java/org/hibernate/sql/ast/tree/select/SortSpecification.java

@@ -10,7 +10,7 @@ import org.hibernate.query.NullPrecedence;
 import org.hibernate.query.SortOrder;
 import org.hibernate.sql.ast.SqlAstWalker;
 import org.hibernate.sql.ast.tree.SqlAstNode;
-import org.hibernate.sql.ast.tree.expression.Collate;
+import org.hibernate.sql.ast.tree.expression.Collation;
 import org.hibernate.sql.ast.tree.expression.Expression;
 
 /**
@@ -20,18 +20,15 @@ public class SortSpecification implements SqlAstNode {
 	private final Expression sortExpression;
 	private final SortOrder sortOrder;
 	private final NullPrecedence nullPrecedence;
+	private final Collation collation;
 
-	public SortSpecification(Expression sortExpression, String collation, SortOrder sortOrder) {
+	public SortSpecification(Expression sortExpression, SortOrder sortOrder) {
-		this( sortExpression, collation, sortOrder, NullPrecedence.NONE );
+		this( sortExpression, null, sortOrder, NullPrecedence.NONE );
 	}
 
 	public SortSpecification(Expression sortExpression, String collation, SortOrder sortOrder, NullPrecedence nullPrecedence) {
-		if ( collation == null ) {
+		this.sortExpression = sortExpression;
-			this.sortExpression = sortExpression;
+		this.collation = collation == null ? null : new Collation(collation);
-		}
-		else {
-			this.sortExpression = new Collate( sortExpression, collation );
-		}
 		this.sortOrder = sortOrder;
 		this.nullPrecedence = nullPrecedence;
 	}
@@ -40,6 +37,10 @@ public class SortSpecification implements SqlAstNode {
 		return sortExpression;
 	}
 
+	public Collation getCollation() {
+		return collation;
+	}
+
 	public SortOrder getSortOrder() {
 		return sortOrder;
 	}

hibernate-core/src/test/java/org/hibernate/orm/test/query/hql/CollateTests.java

@@ -0,0 +1,83 @@
+/*
+ * 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.query.hql;
+
+import org.hibernate.dialect.HSQLDialect;
+import org.hibernate.dialect.MySQLDialect;
+import org.hibernate.dialect.PostgreSQLDialect;
+import org.hibernate.testing.orm.domain.StandardDomainModel;
+import org.hibernate.testing.orm.domain.gambit.EntityOfBasics;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.RequiresDialect;
+import org.hibernate.testing.orm.junit.ServiceRegistry;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.sql.Date;
+import java.sql.Time;
+import java.sql.Timestamp;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+/**
+ * @author Gavin King
+ */
+@ServiceRegistry
+@DomainModel( standardModels = StandardDomainModel.GAMBIT )
+@SessionFactory
+public class CollateTests {
+
+	@BeforeAll
+	public void prepareData(SessionFactoryScope scope) {
+		scope.inTransaction(
+				em -> {
+					EntityOfBasics entity = new EntityOfBasics();
+					entity.setTheString("1234589");
+					entity.setId(123);
+					entity.setTheDate( new Date( 74, 2, 25 ) );
+					entity.setTheTime( new Time( 20, 10, 8 ) );
+					entity.setTheTimestamp( new Timestamp( 121, 4, 27, 13, 22, 50, 123456789 ) );
+					em.persist(entity);
+				}
+		);
+	}
+
+	@Test @RequiresDialect(PostgreSQLDialect.class)
+	public void testCollatePostgreSQL(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createQuery("from EntityOfBasics e where e.theString is not null order by collate(e.theString as ucs_basic)").getResultList();
+					assertThat( session.createQuery("select collate('bar' as ucs_basic) < 'foo'").getSingleResult(), is(true) );
+				}
+		);
+	}
+
+	@Test @RequiresDialect(MySQLDialect.class)
+	public void testCollateMySQL(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createQuery("from EntityOfBasics e order by collate(e.theString as utf8mb4_bin)").getResultList();
+					assertThat( session.createQuery("select collate('bar' as utf8mb4_bin) < 'foo'").getSingleResult(), is(true) );
+				}
+		);
+	}
+
+	@Test @RequiresDialect(HSQLDialect.class)
+	public void testCollateHSQL(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					session.createQuery("from EntityOfBasics e order by collate(e.theString as SQL_TEXT_UCC)").getResultList();
+					session.createQuery("from EntityOfBasics e order by collate(e.theString as English)").getResultList();
+					assertThat( session.createQuery("select collate('bar' as English) < 'foo'").getSingleResult(), is(true) );
+				}
+		);
+	}
+
+}