1 files changed, 6 insertions, 4 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index cf5b73fecfc..c044656e916 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -25063,20 +25063,22 @@ int setup_order(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
       return 1;
     }
 
-    if (!(*order->item)->with_sum_func())
-      continue;
-
     /*
       UNION queries cannot be used with an aggregate function in
       an ORDER BY clause
     */
 
-    if (for_union)
+    if (for_union &&
+        ((*order->item)->with_sum_func() ||
+         (*order->item)->with_window_func()))
     {
       my_error(ER_AGGREGATE_ORDER_FOR_UNION, MYF(0), number);
       return 1;
     }
 
+    if (!(*order->item)->with_sum_func())
+      continue;
+
     if (from_window_spec && (*order->item)->type() != Item::SUM_FUNC_ITEM)
       (*order->item)->split_sum_func(thd, ref_pointer_array,
                                      all_fields, SPLIT_SUM_SELECT);