diff --git a/tests/system-test/2-query/union.py b/tests/system-test/2-query/union.py
index e359164a4f..9086d7754d 100644
--- a/tests/system-test/2-query/union.py
+++ b/tests/system-test/2-query/union.py
@@ -191,7 +191,7 @@ class TDTestCase:
         if tdSql.cursor.istype(col, "BIGINT UNSIGNED"):
             return "BIGINT UNSIGNED"
 
-    def union_check(self):
+    def union_check(self, dbname = "db"):
         sqls = self.sql_list()
         for i in range(len(sqls)):
             tdSql.query(sqls[i])