diff --git a/tests/pytest/fulltest.sh b/tests/pytest/fulltest.sh
index c74fb33c3b67dd49abf2bf8f915d360216aa562f..9ebf1584e224c1bd0732d7e209ffc19db9864399 100755
--- a/tests/pytest/fulltest.sh
+++ b/tests/pytest/fulltest.sh
@@ -187,7 +187,8 @@ python3 ./test.py -f functions/function_top.py
 #python3 ./test.py -f functions/function_twa.py
 python3 queryCount.py
 python3 ./test.py -f query/queryGroupbyWithInterval.py
-python3 client/twoClients.py 
+python3 client/twoClients.py
+python3 test.py -f query/queryInterval.py
 
 # tools
 python3 test.py -f tools/taosdemo.py
diff --git a/tests/pytest/query/queryInterval.py b/tests/pytest/query/queryInterval.py
new file mode 100644
index 0000000000000000000000000000000000000000..db2c3fdeec3370779d1452e8a3875e3149f57bee
--- /dev/null
+++ b/tests/pytest/query/queryInterval.py
@@ -0,0 +1,62 @@
+###################################################################
+#           Copyright (c) 2016 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
+import taos
+from util.log import tdLog
+from util.cases import tdCases
+from util.sql import tdSql
+
+
+class TDTestCase:
+    def init(self, conn, logSql):
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor(), logSql)
+
+        self.ts = 1538548685000
+
+    def run(self):
+        tdSql.prepare()
+
+        tdSql.execute("create table st (ts timestamp, voltage int) tags (loc nchar(30))")
+        tdSql.execute("insert into t0 using st tags('beijing') values(now, 220) (now - 15d, 221) (now - 30d, 225) (now - 35d, 228) (now - 45d, 222)")
+        tdSql.execute("insert into t1 using st tags('shanghai') values(now, 220) (now - 60d, 221) (now - 50d, 225) (now - 40d, 228) (now - 20d, 222)")
+
+        tdSql.query("select avg(voltage) from st interval(1n)")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 1, 223.0)
+        tdSql.checkData(1, 1, 225.0)
+        tdSql.checkData(2, 1, 220.333333)
+        
+        tdSql.query("select avg(voltage) from st interval(1n, 15d)")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 1, 224.8)
+        tdSql.checkData(1, 1, 222.666666)
+        tdSql.checkData(2, 1, 220.0)
+
+        tdSql.query("select avg(voltage) from st interval(1n, 15d) group by loc")
+        tdSql.checkRows(6)
+        tdSql.checkData(0, 1, 225.0)
+        tdSql.checkData(1, 1, 223.0)
+        tdSql.checkData(2, 1, 220.0)
+        tdSql.checkData(3, 1, 224.666666)
+        tdSql.checkData(4, 1, 222.0)
+        tdSql.checkData(5, 1, 220.0)
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success("%s successfully executed" % __file__)
+
+
+tdCases.addWindows(__file__, TDTestCase())
+tdCases.addLinux(__file__, TDTestCase())
diff --git a/tests/pytest/util/sql.py b/tests/pytest/util/sql.py
index 7de8efdfe96c2312a7bb844329fb91f770c54180..9abec354c6d58507ff3bcc74d1c0dc03f691440c 100644
--- a/tests/pytest/util/sql.py
+++ b/tests/pytest/util/sql.py
@@ -123,8 +123,8 @@ class TDSql:
 
     def checkData(self, row, col, data):
         self.checkRowCol(row, col) 
-        if self.queryResult[row][col] != data:
-            if str(self.queryResult[row][col]) != str(data):
+        if self.queryResult[row][col] != data:            
+            if str(self.queryResult[row][col]) == str(data):
                 tdLog.info("sql:%s, row:%d col:%d data:%s == expect:%s" %
                             (self.sql, row, col, self.queryResult[row][col], data)) 
                 return