diff --git a/tests/develop-test/2-query/4-union/union-order.py b/tests/develop-test/2-query/4-union/union-order.py
new file mode 100644
index 0000000000000000000000000000000000000000..6c2f20c129d294601f89757d01710f5e080a1717
--- /dev/null
+++ b/tests/develop-test/2-query/4-union/union-order.py
@@ -0,0 +1,60 @@
+###################################################################
+#           Copyright (c) 2021 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+
+import sys
+from util.log import *
+from util.cases import *
+from util.sql import *
+
+
+class TDTestCase:
+    def caseDescription(self):
+        '''
+        case1<shenglian zhou>: [TD-12229]fix union all query produces different result when switch query
+        ''' 
+        return
+    
+    def init(self, conn, logSql):
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor(), logSql)
+        self._conn = conn
+
+    def run(self):
+        print("running {}".format(__file__))
+        tdSql.execute("drop database if exists td12229")
+        tdSql.execute("create database if not exists td12229")
+        tdSql.execute('use td12229')
+
+        tdSql.execute('create stable st(ts timestamp , value int ) tags (ind int)') 
+        tdSql.execute('insert into tb1 using st tags(1) values(now ,1)') 
+        tdSql.execute('insert into tb1 using st tags(1) values(now+1s ,2)') 
+        tdSql.execute('insert into tb1 using st tags(1) values(now+2s ,3)') 
+        tdSql.execute('create stable ste(ts timestamp , value int ) tags (ind int)') 
+        tdSql.query('select * from st')
+        tdSql.checkRows(3)
+        tdSql.query('select * from st union all select * from ste')
+        tdSql.checkRows(3)
+        tdSql.query('select * from ste union all select * from st')
+        tdSql.checkRows(3)
+        tdSql.query('select elapsed(ts) from ste group by tbname union all select elapsed(ts) from st group by tbname;')
+        tdSql.checkRows(1)
+        tdSql.query('select elapsed(ts) from st group by tbname union all select elapsed(ts) from ste group by tbname;')
+        tdSql.checkRows(1)
+        tdSql.execute('drop database td12229')
+    def stop(self):
+        tdSql.close()
+        tdLog.success("%s successfully executed" % __file__)
+
+
+tdCases.addWindows(__file__, TDTestCase())
+tdCases.addLinux(__file__, TDTestCase())
diff --git a/tests/develop-test/fulltest.sh b/tests/develop-test/fulltest.sh
index 9ec1dd23ac27928950befc35bd49ba8b4e6270eb..f83cb6f3f35aea35c6f7b61b9172e53f6060a119 100755
--- a/tests/develop-test/fulltest.sh
+++ b/tests/develop-test/fulltest.sh
@@ -1,3 +1,4 @@
 python3 test.py -f 0-management/3-tag/json_tag.py
 python3 test.py -f 1-insert/0-sql/basic.py
-python3 test.py -f 1-insert/0-sql/batchInsert.py
\ No newline at end of file
+python3 test.py -f 1-insert/0-sql/batchInsert.py
+python3 test.py -f 2-query/4-union/union-order.py