HHH-15360 Fix listagg rendering on older H2 versions

hibernate-core/src/main/java/org/hibernate/dialect/H2Dialect.java

@@ -315,11 +315,15 @@ public class H2Dialect extends Dialect {
 		functionFactory.rownum();
 		if ( getVersion().isSameOrAfter( 1, 4, 200 ) ) {
 			functionFactory.windowFunctions();
-			functionFactory.listagg( null );
 			if ( getVersion().isSameOrAfter( 2 ) ) {
+				functionFactory.listagg( null );
 				functionFactory.inverseDistributionOrderedSetAggregates();
 				functionFactory.hypotheticalOrderedSetAggregates();
 			}
+			else {
+				// Use group_concat until 2.x as listagg was buggy
+				functionFactory.listagg_groupConcat();
+			}
 		}
 		else {
 			functionFactory.listagg_groupConcat();

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

@@ -12,6 +12,7 @@ import org.hibernate.LockMode;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.internal.util.collections.CollectionHelper;
 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;
@@ -198,6 +199,12 @@ public class H2SqlAstTranslator<T extends JdbcOperation> extends AbstractSqlAstT
 		return getDialect().getVersion().isSameOrAfter( 1, 4, 197 );
 	}
 
+	@Override
+	protected boolean supportsNullPrecedence() {
+		// Support for nulls clause in listagg was added in 2.0
+		return getClauseStack().getCurrent() != Clause.WITHIN_GROUP || getDialect().getVersion().isSameOrAfter( 2 );
+	}
+
 	@Override
 	protected String getFromDual() {
 		return " from dual";

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

@@ -590,7 +590,7 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
 
 	@Override
 	public boolean supportsNullPrecedence() {
-		return getVersion().isBefore( 10 );
+		return false;
 	}
 
 	@Override

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

@@ -2230,7 +2230,8 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 		}
 		final boolean renderNullPrecedence = nullPrecedence != null &&
 				!nullPrecedence.isDefaultOrdering( sortOrder, getDialect().getNullOrdering() );
-		if ( renderNullPrecedence && !getDialect().supportsNullPrecedence() ) {
+		final boolean supportsNullPrecedence = renderNullPrecedence && supportsNullPrecedence();
+		if ( renderNullPrecedence && !supportsNullPrecedence ) {
 			emulateSortSpecificationNullPrecedence( sortExpression, nullPrecedence );
 		}
 
@@ -2248,12 +2249,16 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
 			appendSql( " desc" );
 		}
 
-		if ( renderNullPrecedence && getDialect().supportsNullPrecedence() ) {
+		if ( renderNullPrecedence && supportsNullPrecedence ) {
 			appendSql( " nulls " );
 			appendSql( nullPrecedence == NullPrecedence.LAST ? "last" : "first" );
 		}
 	}
 
+	protected boolean supportsNullPrecedence() {
+		return getDialect().supportsNullPrecedence();
+	}
+
 	protected void emulateSortSpecificationNullPrecedence(Expression sortExpression, NullPrecedence nullPrecedence) {
 		// TODO: generate "virtual" select items and use them here positionally
 		appendSql( "case when (" );

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

@@ -10,6 +10,7 @@ import java.util.Arrays;
 import java.util.Date;
 import java.util.List;
 
+import org.hibernate.testing.TestForIssue;
 import org.hibernate.testing.orm.domain.StandardDomainModel;
 import org.hibernate.testing.orm.domain.gambit.EntityOfBasics;
 import org.hibernate.testing.orm.junit.DialectFeatureChecks;
@@ -136,6 +137,18 @@ public class OrderedSetAggregateTest {
 		);
 	}
 
+	@Test
+	@TestForIssue( jiraKey = "HHH-15360")
+	@RequiresDialectFeature(feature = DialectFeatureChecks.SupportsStringAggregation.class)
+	public void testListaggWithNullsClause(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					TypedQuery<String> q = session.createQuery( "select listagg(eob.theString, ',') within group (order by eob.id desc nulls first) from EntityOfBasics eob", String.class );
+					assertEquals( "5,13,7,6,5", q.getSingleResult() );
+				}
+		);
+	}
+
 	@Test
 	@RequiresDialectFeature(feature = DialectFeatureChecks.SupportsInverseDistributionFunctions.class)
 	public void testInverseDistribution(SessionFactoryScope scope) {