diff --git a/mysql-test/main/group_by.test b/mysql-test/main/group_by.test
index 19f2e6582ae44..69a1315ff9636 100644
--- a/mysql-test/main/group_by.test
+++ b/mysql-test/main/group_by.test
@@ -1786,6 +1786,7 @@ DROP TABLE t1;
 --echo #
 
 SET sql_mode='ONLY_FULL_GROUP_BY';
+--sorted_result
 SELECT 1 AS test UNION SELECT 2 AS test ORDER BY test IS NULL ASC;
 SET sql_mode='';