diff --git a/tests/system-test/2-query/Timediff.py b/tests/system-test/2-query/Timediff.py
index d9bac2e930..1f73215dd5 100644
--- a/tests/system-test/2-query/Timediff.py
+++ b/tests/system-test/2-query/Timediff.py
@@ -16,6 +16,7 @@ class TDTestCase:
             '2020-5-1 00:00:00.001002001'
 
         ]
+        self.rest_tag = str(conn).lower().split('.')[0].replace("<taos","")
         self.db_param_precision = ['ms','us','ns']
         self.time_unit = ['1w','1d','1h','1m','1s','1a','1u','1b']
         self.error_unit = ['2w','2d','2h','2m','2s','2a','2u','1c','#1']
@@ -101,33 +102,34 @@ class TDTestCase:
                 for i in range(len(self.ts_str)):
                     tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i])-self.subtractor*1000000)))
             elif precision.lower() == 'ns':
-                self.check_tb_type(unit,tb_type)
-                tdSql.checkRows(len(self.ts_str))
-                if unit.lower() == '1w':
+                if self.rest_tag != 'rest':
+                    self.check_tb_type(unit,tb_type)
+                    tdSql.checkRows(len(self.ts_str))
+                    if unit.lower() == '1w':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60/60/24/7))
+                    elif unit.lower() == '1d':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60/60/24))
+                    elif unit.lower() == '1h':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60/60))
+                    elif unit.lower() == '1m':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60))
+                    elif unit.lower() == '1s':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)))
+                    elif unit.lower() == '1a':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000)-self.subtractor*1000)))
+                    elif unit.lower() == '1u':
+                        for i in range(len(self.ts_str)):
+                            tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000)-self.subtractor*1000000)))
+                    self.check_tbtype(tb_type)
+                    tdSql.checkRows(len(self.ts_str))
                     for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60/60/24/7))
-                elif unit.lower() == '1d':
-                    for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60/60/24))
-                elif unit.lower() == '1h':
-                    for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60/60))
-                elif unit.lower() == '1m':
-                    for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)/60))
-                elif unit.lower() == '1s':
-                    for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000000)-self.subtractor)))
-                elif unit.lower() == '1a':
-                    for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000000)-self.subtractor*1000)))
-                elif unit.lower() == '1u':
-                    for i in range(len(self.ts_str)):
-                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i]/1000)-self.subtractor*1000000)))
-                self.check_tbtype(tb_type)
-                tdSql.checkRows(len(self.ts_str))
-                for i in range(len(self.ts_str)):
-                    tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i])-self.subtractor*1000000000)))
+                        tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i])-self.subtractor*1000000000)))
             for unit in self.error_unit:
                 if tb_type.lower() == 'ntb':
                     tdSql.error(f'select timediff(ts,{self.subtractor},{unit}) from {self.ntbname}')
@@ -162,10 +164,35 @@ class TDTestCase:
             date_time = self.get_time.time_transform(self.ts_str,precision)
             self.data_check(date_time,precision,'ctb')
             self.data_check(date_time,precision,'stb')
-    def run(self):  # sourcery skip: extract-duplicate-method
+    def function_without_param(self):
+        for precision in self.db_param_precision:
+            tdSql.execute(f'drop database if exists {self.dbname}')
+            tdSql.execute(f'create database {self.dbname} precision "{precision}"')
+            tdSql.execute(f'use {self.dbname}')
+            tdSql.execute(f'create table {self.stbname} (ts timestamp,c0 int) tags(t0 int)')
+            tdSql.execute(f'create table {self.ctbname} using {self.stbname} tags(1)')
+            for ts in self.ts_str:
+                tdSql.execute(f'insert into {self.ctbname} values("{ts}",1)')
+            date_time = self.get_time.time_transform(self.ts_str,precision)
+            tdSql.query(f'select timediff(ts,{self.subtractor}) from {self.ctbname}')
+            if precision.lower() == 'ms':
+                for i in range(len(self.ts_str)):
+                    tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i])-self.subtractor*1000)))
+            elif precision.lower() == 'us':
+                for i in range(len(self.ts_str)):
+                    tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i])-self.subtractor*1000000)))
+            elif precision.lower() == 'ns':
+                for i in range(len(self.ts_str)):
+                    tdSql.checkEqual(tdSql.queryResult[i][0],int(((date_time[i])-self.subtractor*1000000000)))
+                    
 
+
+
+
+    def run(self):  # sourcery skip: extract-duplicate-method
         self.function_check_ntb()
         self.function_check_stb()
+        self.function_without_param()
         
     def stop(self):
         tdSql.close()
diff --git a/tests/system-test/2-query/avg.py b/tests/system-test/2-query/avg.py
index 884b8c087c..5ba0a91a7e 100644
--- a/tests/system-test/2-query/avg.py
+++ b/tests/system-test/2-query/avg.py
@@ -1,12 +1,11 @@
 import taos
 import sys
-import datetime
-import inspect
-
+import numpy as np
 from util.log import *
 from util.sql import *
 from util.cases import *
-
+from util.sqlset import TDSetSql
+from util.common import *
 class TDTestCase:
     # updatecfgDict = {'debugFlag': 143 ,"cDebugFlag":143,"uDebugFlag":143 ,"rpcDebugFlag":143 , "tmrDebugFlag":143 ,
     # "jniDebugFlag":143 ,"simDebugFlag":143,"dDebugFlag":143, "dDebugFlag":143,"vDebugFlag":143,"mDebugFlag":143,"qDebugFlag":143,
@@ -14,6 +13,51 @@ class TDTestCase:
     def init(self, conn, logSql):
         tdLog.debug(f"start to excute {__file__}")
         tdSql.init(conn.cursor(), False)
+        self.setsql = TDSetSql()
+        self.column_dict = {
+            'ts':'timestamp',
+            'col1': 'tinyint',
+            'col2': 'smallint',
+            'col3': 'int',
+            'col4': 'bigint',
+            'col5': 'tinyint unsigned',
+            'col6': 'smallint unsigned',
+            'col7': 'int unsigned',
+            'col8': 'bigint unsigned',
+    
+        }
+        self.dbname = tdCom.getLongName(3,"letters")
+        self.row_num = 10
+        self.ts = 1537146000000
+    def insert_data(self,column_dict,tbname,row_num):
+        insert_sql = self.setsql.set_insertsql(column_dict,tbname)
+        for i in range(row_num):
+            insert_list = []
+            self.setsql.insert_values(column_dict,i,insert_sql,insert_list,self.ts)
+
+    def avg_check_unsigned(self):
+        stbname = f'{self.dbname}.{tdCom.getLongName(5,"letters")}'
+        tag_dict = {
+            't0':'int'
+        }
+        tag_values = [
+            f'1'
+            ]
+        tdSql.execute(f"create database if not exists {self.dbname}")
+        tdSql.execute(self.setsql.set_create_stable_sql(stbname,self.column_dict,tag_dict))
+        tdSql.execute(f"create table {stbname}_1 using {stbname} tags({tag_values[0]})")
+        self.insert_data(self.column_dict,f'{stbname}_1',self.row_num)
+        for col in self.column_dict.keys():
+            col_val_list = []
+            if col.lower() != 'ts':
+                tdSql.query(f'select {col} from {stbname}_1')
+                sum_val = 0
+                for col_val in tdSql.queryResult:
+                    col_val_list.append(col_val[0])
+                col_avg = np.mean(col_val_list)
+                tdSql.query(f'select avg({col}) from {stbname}_1')
+                tdSql.checkEqual(col_avg,tdSql.queryResult[0][0])
+        tdSql.execute(f'drop database {self.dbname}')
 
     def prepare_datas(self, dbname="db"):
         tdSql.execute(
@@ -412,6 +456,7 @@ class TDTestCase:
         tdLog.printNoPrefix("==========step6: avg filter query ============")
 
         self.avg_func_filter()
+        self.avg_check_unsigned()
 
     def stop(self):
         tdSql.close()
diff --git a/tests/system-test/2-query/stddev.py b/tests/system-test/2-query/stddev.py
new file mode 100644
index 0000000000..837353dfc9
--- /dev/null
+++ b/tests/system-test/2-query/stddev.py
@@ -0,0 +1,79 @@
+###################################################################
+#           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 random
+import string
+import numpy as np
+from util.log import *
+from util.cases import *
+from util.sql import *
+from util.common import *
+from util.sqlset import *
+class TDTestCase:
+    def init(self, conn, logSql):
+        tdLog.debug("start to execute %s" % __file__)
+        tdSql.init(conn.cursor())
+        self.dbname = 'db_test'
+        self.setsql = TDSetSql()
+        self.ntbname = f'{self.dbname}.ntb'
+        self.row_num = 10
+        self.ts = 1537146000000
+        self.column_dict = {
+            'ts':'timestamp',
+            'col1': 'tinyint',
+            'col2': 'smallint',
+            'col3': 'int',
+            'col4': 'bigint',
+            'col5': 'tinyint unsigned',
+            'col6': 'smallint unsigned',
+            'col7': 'int unsigned',
+            'col8': 'bigint unsigned',
+    
+        }
+    def insert_data(self,column_dict,tbname,row_num):
+        insert_sql = self.setsql.set_insertsql(column_dict,tbname)
+        for i in range(row_num):
+            insert_list = []
+            self.setsql.insert_values(column_dict,i,insert_sql,insert_list,self.ts)
+    def stddev_check(self):
+        stbname = f'{self.dbname}.{tdCom.getLongName(5,"letters")}'
+        tag_dict = {
+            't0':'int'
+        }
+        tag_values = [
+            f'1'
+            ]
+        tdSql.execute(f"create database if not exists {self.dbname}")
+        tdSql.execute(self.setsql.set_create_stable_sql(stbname,self.column_dict,tag_dict))
+        tdSql.execute(f"create table {stbname}_1 using {stbname} tags({tag_values[0]})")
+        self.insert_data(self.column_dict,f'{stbname}_1',self.row_num)
+        for col in self.column_dict.keys():
+            col_val_list = []
+            if col.lower() != 'ts':
+                tdSql.query(f'select {col} from {stbname}_1')
+                for col_val in tdSql.queryResult:
+                    col_val_list.append(col_val[0])
+                col_std = np.std(col_val_list)
+                tdSql.query(f'select stddev({col}) from {stbname}_1')
+                tdSql.checkEqual(col_std,tdSql.queryResult[0][0])
+        tdSql.execute(f'drop database {self.dbname}')
+    def run(self): 
+        self.stddev_check() 
+        
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success(f"{__file__} successfully executed")
+
+tdCases.addLinux(__file__, TDTestCase())
+tdCases.addWindows(__file__, TDTestCase())
diff --git a/tests/system-test/2-query/timetruncate.py b/tests/system-test/2-query/timetruncate.py
index 8d1c9214e9..4cc6b27d64 100644
--- a/tests/system-test/2-query/timetruncate.py
+++ b/tests/system-test/2-query/timetruncate.py
@@ -180,7 +180,8 @@ class TDTestCase:
             date_time = self.get_time.time_transform(self.ts_str,precision)
             self.data_check(date_time,precision,'ctb')
             self.data_check(date_time,precision,'stb')
-
+    
+   
     def run(self):
         self.function_check_ntb()
         self.function_check_stb()