[CALCITE-6063] ARRAY subquery with OrderBy loses Sort

core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java

@@ -5538,7 +5538,7 @@ ImmutableList<RelNode> retrieveCursors() {
         case ARRAY_QUERY_CONSTRUCTOR:
           call = (SqlCall) expr;
           query = Iterables.getOnlyElement(call.getOperandList());
-          root = convertQueryRecursive(query, false, null);
+          root = convertQueryRecursive(query, true, null);
           return RexSubQuery.array(root.rel);
 
         case MAP_QUERY_CONSTRUCTOR:

core/src/test/resources/sql/sub-query.iq

@@ -3726,4 +3726,52 @@ SELECT map(SELECT empno, deptno from emp where false);
 
 !ok
 
+# [CALCITE-6063] ARRAY subquery with OrderBy loses Sort
+# normal behavior
+SELECT array(SELECT empno FROM emp);
++--------------------------------------------------------------------------------------+
+| EXPR$0                                                                               |
++--------------------------------------------------------------------------------------+
+| [7369, 7499, 7521, 7566, 7654, 7698, 7782, 7788, 7839, 7844, 7876, 7900, 7902, 7934] |
++--------------------------------------------------------------------------------------+
+(1 row)
+
+!ok
+
+# [CALCITE-6063] ARRAY subquery with OrderBy loses Sort
+# with filter
+SELECT array(SELECT empno FROM emp WHERE empno > 7800);
++--------------------------------------+
+| EXPR$0                               |
++--------------------------------------+
+| [7839, 7844, 7876, 7900, 7902, 7934] |
++--------------------------------------+
+(1 row)
+
+!ok
+
+# [CALCITE-6063] ARRAY subquery with OrderBy loses Sort
+# with filter and order by
+SELECT array(SELECT empno FROM emp WHERE empno > 7800 ORDER BY empno DESC);
++--------------------------------------+
+| EXPR$0                               |
++--------------------------------------+
+| [7934, 7902, 7900, 7876, 7844, 7839] |
++--------------------------------------+
+(1 row)
+
+!ok
+
+# [CALCITE-6063] ARRAY subquery with OrderBy loses Sort
+# with filter and order by and limit
+SELECT array(SELECT empno FROM emp WHERE empno > 7800 ORDER BY empno DESC LIMIT 2);
++--------------+
+| EXPR$0       |
++--------------+
+| [7934, 7902] |
++--------------+
+(1 row)
+
+!ok
+
 # End sub-query.iq

site/_docs/reference.md

@@ -1643,6 +1643,14 @@ Implicit type coercion of following cases are ignored:
 | ARRAY '[' value [, value ]* ']' | Creates an array from a list of values.
 | MAP '[' key, value [, key, value ]* ']' | Creates a map from a list of key-value pairs.
 
+### Value constructors by query
+
+| Operator syntax                    | Description |
+|:-----------------------------------|:------------|
+| ARRAY (sub-query)                  | Creates an array from the result of a sub-query. Example: `ARRAY(SELECT empno FROM emp)` |
+| MAP (sub-query)                    | Creates a map from the result of a key-value pair sub-query. Example: `MAP(SELECT empno, deptno FROM emp)` |
+| MULTISET (sub-query)               | Creates a multiset from the result of a sub-query. Example: `MULTISET(SELECT empno FROM emp)` |
+
 ### Collection functions
 
 | Operator syntax | Description

testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java

@@ -10697,20 +10697,41 @@ private static void checkArrayConcatAggFuncFails(SqlOperatorFixture t) {
         "[1         , 2         , Hi        , null]", "CHAR(10) ARRAY NOT NULL");
   }
 
-  /**
-   * Test case for
-   * <a href="https://issues.apache.org/jira/browse/CALCITE-4999">[CALCITE-4999]
-   * ARRAY, MULTISET functions should return an collection of scalars
-   * if a sub-query returns 1 column</a>.
-   */
   @Test void testArrayQueryConstructor() {
     final SqlOperatorFixture f = fixture();
     f.setFor(SqlStdOperatorTable.ARRAY_QUERY, SqlOperatorFixture.VmName.EXPAND);
+
+    // Test case for [CALCITE-4999] ARRAY, MULTISET functions should
+    // return a collection of scalars if a sub-query returns 1 column
     f.checkScalar("array(select 1)", "[1]",
         "INTEGER NOT NULL ARRAY NOT NULL");
     f.check("select array(select ROW(1,2))",
         "RecordType(INTEGER NOT NULL EXPR$0, INTEGER NOT NULL EXPR$1) NOT NULL ARRAY NOT NULL",
         "[{1, 2}]");
+
+    // single sub-clause test
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x))",
+        "INTEGER NOT NULL ARRAY NOT NULL", "[1, 2, 3, 4]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) where x > 1)",
+        "INTEGER NOT NULL ARRAY NOT NULL", "[2, 3, 4]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) limit 2)",
+        "INTEGER NOT NULL ARRAY NOT NULL", "[1, 2]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) where x > 1 limit 2)",
+        "INTEGER NOT NULL ARRAY NOT NULL", "[2, 3]");
+
+    // combined tests
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) "
+        + "order by x asc)", "INTEGER NOT NULL ARRAY NOT NULL", "[1, 2, 3, 4]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) "
+        + "where x > 1 order by x asc)", "INTEGER NOT NULL ARRAY NOT NULL", "[2, 3, 4]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) "
+        + "where x > 1 order by x asc limit 2)", "INTEGER NOT NULL ARRAY NOT NULL", "[2, 3]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) "
+        + "order by x desc)", "INTEGER NOT NULL ARRAY NOT NULL", "[4, 3, 2, 1]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) "
+        + "where x > 1 order by x desc)", "INTEGER NOT NULL ARRAY NOT NULL", "[4, 3, 2]");
+    f.check("select array(select x from unnest(array[1,2,3,4]) as t(x) "
+        + "where x > 1 order by x desc limit 2)", "INTEGER NOT NULL ARRAY NOT NULL", "[4, 3]");
   }
 
   /**