HHH-17355 Add array_agg documentation and add it to NodeBuilder

Author: beikov

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

@@ -1118,6 +1118,7 @@ The following functions deal with SQL array types, which are not supported on ev
 | Function | Purpose
 
 | `array()` | Creates an array based on the passed arguments
+| `array_agg()` | Aggregates row values into an array
 | `array_position()` | Determines the position of an element in an array
 | `array_length()` | Determines the length of an array
 | `array_concat()` | Concatenates array with each other in order
@@ -1147,6 +1148,18 @@ include::{array-example-dir-hql}/ArrayConstructorTest.java[tags=hql-array-exampl
 ----
 ====
 
+===== `array_agg()`
+
+An <<hql-aggregate-functions-orderedset,ordered set aggregate function>> that aggregates values to an array.
+
+[[hql-array-agg-example]]
+====
+[source, JAVA, indent=0]
+----
+include::{array-example-dir-hql}/ArrayAggregateTest.java[tags=hql-array-agg-example]
+----
+====
+
 [[hql-array-position-functions]]
 ===== `array_position()`
 

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

@@ -17,6 +17,7 @@
 import java.util.Map;
 import java.util.Set;
 
+import org.hibernate.Incubating;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.metamodel.model.domain.JpaMetamodel;
 import org.hibernate.query.NullPrecedence;
@@ -25,10 +26,13 @@
 import org.hibernate.query.criteria.JpaCoalesce;
 import org.hibernate.query.criteria.JpaCompoundSelection;
 import org.hibernate.query.criteria.JpaExpression;
+import org.hibernate.query.criteria.JpaOrder;
 import org.hibernate.query.criteria.JpaParameterExpression;
+import org.hibernate.query.criteria.JpaPredicate;
 import org.hibernate.query.criteria.JpaSearchedCase;
 import org.hibernate.query.criteria.JpaSelection;
 import org.hibernate.query.criteria.JpaSimpleCase;
+import org.hibernate.query.criteria.JpaWindow;
 import org.hibernate.query.spi.QueryEngine;
 import org.hibernate.query.sqm.tree.delete.SqmDeleteStatement;
 import org.hibernate.query.sqm.tree.domain.SqmBagJoin;
@@ -100,6 +104,43 @@ <R> SqmTuple<R> tuple(
 	// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 	// Array functions for array types
 
+	/**
+	 * @see #arrayAgg(JpaOrder, JpaPredicate, JpaWindow, Expression)
+	 * @since 6.4
+	 */
+	<T> JpaExpression<T[]> arrayAgg(JpaOrder order, Expression<? extends T> argument);
+
+	/**
+	 * @see #arrayAgg(JpaOrder, JpaPredicate, JpaWindow, Expression)
+	 * @since 6.4
+	 */
+	<T> JpaExpression<T[]> arrayAgg(JpaOrder order, JpaPredicate filter, Expression<? extends T> argument);
+
+	/**
+	 * @see #arrayAgg(JpaOrder, JpaPredicate, JpaWindow, Expression)
+	 * @since 6.4
+	 */
+	<T> JpaExpression<T[]> arrayAgg(JpaOrder order, JpaWindow window, Expression<? extends T> argument);
+
+	/**
+	 * Create a {@code array_agg} ordered set-aggregate function expression.
+	 *
+	 * @param order order by clause used in within group
+	 * @param filter optional filter clause
+	 * @param window optional window over which to apply the function
+	 * @param argument values to aggregate
+	 *
+	 * @return ordered set-aggregate expression
+	 *
+	 * @see #functionWithinGroup(String, Class, JpaOrder, JpaPredicate, JpaWindow, Expression...)
+	 * @since 6.4
+	 */
+	<T> JpaExpression<T[]> arrayAgg(
+			JpaOrder order,
+			JpaPredicate filter,
+			JpaWindow window,
+			Expression<? extends T> argument);
+
 	/**
 	 * Creates an array literal with the {@code array} constructor function.
 	 *

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

@@ -3632,6 +3632,30 @@ public SqmExpression<Double> percentRank(
 		return functionWithinGroup( "percent_rank", Double.class, order, filter, window, arguments );
 	}
 
+	@Override
+	public <T> JpaExpression<T[]> arrayAgg(JpaOrder order, Expression<? extends T> argument) {
+		return arrayAgg( order, null, null, argument );
+	}
+
+	@Override
+	public <T> JpaExpression<T[]> arrayAgg(JpaOrder order, JpaPredicate filter, Expression<? extends T> argument) {
+		return arrayAgg( order, filter, null, argument );
+	}
+
+	@Override
+	public <T> JpaExpression<T[]> arrayAgg(JpaOrder order, JpaWindow window, Expression<? extends T> argument) {
+		return arrayAgg( order, null, window, argument );
+	}
+
+	@Override
+	public <T> JpaExpression<T[]> arrayAgg(
+			JpaOrder order,
+			JpaPredicate filter,
+			JpaWindow window,
+			Expression<? extends T> argument) {
+		return functionWithinGroup( "array_agg", null, order, filter, window, argument );
+	}
+
 	@Override
 	public <T> SqmExpression<T[]> arrayLiteral(T... elements) {
 		return getFunctionDescriptor( "array" ).generateSqmExpression(

hibernate-core/src/test/java/org/hibernate/orm/test/function/array/ArrayAggregateTest.java

@@ -109,8 +109,10 @@ public void cleanup(SessionFactoryScope scope) {
 	@Test
 	public void testEmpty(SessionFactoryScope scope) {
 		scope.inSession( em -> {
+			//tag::hql-array-agg-example[]
 			List<String[]> results = em.createQuery( "select array_agg(e.data) within group (order by e.id) from BasicEntity e", String[].class )
 					.getResultList();
+			//end::hql-array-agg-example[]
 			assertEquals( 1, results.size() );
 			assertNull( results.get( 0 ) );
 		} );