diff --git a/tests/system-test/2-query/diff.py b/tests/system-test/2-query/diff.py
index 80e0d3b10d..8f3fb2c3d9 100644
--- a/tests/system-test/2-query/diff.py
+++ b/tests/system-test/2-query/diff.py
@@ -21,6 +21,7 @@ class TDTestCase:
             tdSql.checkData(i, 0, 1);
     
     def full_datatype_test(self):
+        tdSql.execute("use db;")
         sql = "create table st(ts timestamp, c1 bool, c2 float, c3 double,c4 tinyint, c5 smallint, c6 int, c7 bigint, c8 tinyint unsigned, c9 smallint unsigned, c10 int unsigned, c11 bigint unsigned) tags( area int);"
         tdSql.execute(sql)