diff --git a/tests/system-test/2-query/bottom.py b/tests/system-test/2-query/bottom.py
index 6b7e6179c3..1037b0a8f3 100644
--- a/tests/system-test/2-query/bottom.py
+++ b/tests/system-test/2-query/bottom.py
@@ -16,6 +16,7 @@ import string
 from util.log import *
 from util.cases import *
 from util.sql import *
+from util.common import *
 
 
 
@@ -29,20 +30,6 @@ class TDTestCase:
         self.ts = 1537146000000
         self.binary_str = 'taosdata'
         self.nchar_str = '涛思数据'
-    def get_long_name(self, length, mode="mixed"):
-        """
-        generate long name
-        mode could be numbers/letters/letters_mixed/mixed
-        """
-        if mode == "numbers":
-            population = string.digits
-        elif mode == "letters":
-            population = string.ascii_letters.lower()
-        elif mode == "letters_mixed":
-            population = string.ascii_letters.upper() + string.ascii_letters.lower()
-        else:
-            population = string.ascii_letters.lower() + string.digits
-        return "".join(random.choices(population, k=length))
     def bottom_check_base(self):
         tdSql.prepare()
         tdSql.execute('''create table stb(ts timestamp, col1 tinyint, col2 smallint, col3 int, col4 bigint, col5 tinyint unsigned, col6 smallint unsigned, 
@@ -72,8 +59,8 @@ class TDTestCase:
         tdSql.execute('drop database db')
     def bottom_check_distribute(self):
         # prepare data for vgroup 4
-        dbname = self.get_long_name(length=10, mode="letters")
-        stbname = self.get_long_name(length=5, mode="letters")
+        dbname = tdCom.getLongName(5, "letters")
+        stbname = tdCom.getLongName(5, "letters")
         vgroup_num = 2
         child_table_num = 20
         tdSql.execute(f"create database if not exists {dbname} vgroups {vgroup_num}")
diff --git a/tests/system-test/2-query/first.py b/tests/system-test/2-query/first.py
index 8875bfe748..e9a8cc950b 100644
--- a/tests/system-test/2-query/first.py
+++ b/tests/system-test/2-query/first.py
@@ -15,6 +15,7 @@ import random
 import string
 import sys
 import taos
+from util.common import *
 from util.log import *
 from util.cases import *
 from util.sql import *
@@ -32,20 +33,6 @@ class TDTestCase:
         self.binary_str = 'taosdata'
         self.nchar_str = '涛思数据'
     
-    def get_long_name(self, length, mode="mixed"):
-        """
-        generate long name
-        mode could be numbers/letters/letters_mixed/mixed
-        """
-        if mode == "numbers":
-            population = string.digits
-        elif mode == "letters":
-            population = string.ascii_letters.lower()
-        elif mode == "letters_mixed":
-            population = string.ascii_letters.upper() + string.ascii_letters.lower()
-        else:
-            population = string.ascii_letters.lower() + string.digits
-        return "".join(random.choices(population, k=length))
     def first_check_base(self):
         tdSql.prepare()
         column_dict = {
@@ -110,8 +97,8 @@ class TDTestCase:
         tdSql.execute('drop database db')
     def first_check_stb_distribute(self):
         # prepare data for vgroup 4
-        dbname = self.get_long_name(length=10, mode="letters")
-        stbname = self.get_long_name(length=5, mode="letters")
+        dbname = tdCom.getLongName(10, "letters")
+        stbname = tdCom.getLongName(5, "letters")
         child_table_num = 20
         vgroup = 2
         column_dict = {
diff --git a/tests/system-test/2-query/last.py b/tests/system-test/2-query/last.py
index d74f88745c..ee65d22a22 100644
--- a/tests/system-test/2-query/last.py
+++ b/tests/system-test/2-query/last.py
@@ -3,6 +3,7 @@ import string
 from util.log import *
 from util.cases import *
 from util.sql import *
+from util.common import *
 import numpy as np
 
 
@@ -17,21 +18,6 @@ class TDTestCase:
         self.binary_str = 'taosdata'
         self.nchar_str = '涛思数据'
 
-    def get_long_name(self, length, mode="mixed"):
-        """
-        generate long name
-        mode could be numbers/letters/letters_mixed/mixed
-        """
-        if mode == "numbers":
-            population = string.digits
-        elif mode == "letters":
-            population = string.ascii_letters.lower()
-        elif mode == "letters_mixed":
-            population = string.ascii_letters.upper() + string.ascii_letters.lower()
-        else:
-            population = string.ascii_letters.lower() + string.digits
-        return "".join(random.choices(population, k=length))
-
     def set_create_normaltable_sql(self, ntbname, column_dict):
         column_sql = ''
         for k, v in column_dict.items():
@@ -51,7 +37,7 @@ class TDTestCase:
     
     def last_check_stb_tb_base(self):
         tdSql.prepare()
-        stbname = self.get_long_name(length=5, mode="letters")
+        stbname = tdCom.getLongName(5, "letters")
         column_dict = {
             'col1': 'tinyint',
             'col2': 'smallint',
@@ -127,7 +113,7 @@ class TDTestCase:
 
     def last_check_ntb_base(self):
         tdSql.prepare()
-        ntbname = self.get_long_name(length=5, mode="letters")
+        ntbname = tdCom.getLongName(5, "letters")
         column_dict = {
             'col1': 'tinyint',
             'col2': 'smallint',
@@ -191,8 +177,8 @@ class TDTestCase:
 
     def last_check_stb_distribute(self):
         # prepare data for vgroup 4
-        dbname = self.get_long_name(length=10, mode="letters")
-        stbname = self.get_long_name(length=5, mode="letters")
+        dbname = tdCom.getLongName(10, "letters")
+        stbname = tdCom.getLongName(5, "letters")
         vgroup_num = 4
         column_dict = {
             'col1': 'tinyint',
diff --git a/tests/system-test/2-query/top.py b/tests/system-test/2-query/top.py
index acd6bb12e9..83f535856e 100644
--- a/tests/system-test/2-query/top.py
+++ b/tests/system-test/2-query/top.py
@@ -13,6 +13,7 @@
 
 import random
 import string
+from util.common import *
 from util.log import *
 from util.cases import *
 from util.sql import *
@@ -28,20 +29,6 @@ class TDTestCase:
         self.ts = 1537146000000
         self.binary_str = 'taosdata'
         self.nchar_str = '涛思数据'
-    def get_long_name(self, length, mode="mixed"):
-        """
-        generate long name
-        mode could be numbers/letters/letters_mixed/mixed
-        """
-        if mode == "numbers":
-            population = string.digits
-        elif mode == "letters":
-            population = string.ascii_letters.lower()
-        elif mode == "letters_mixed":
-            population = string.ascii_letters.upper() + string.ascii_letters.lower()
-        else:
-            population = string.ascii_letters.lower() + string.digits
-        return "".join(random.choices(population, k=length))
     def top_check_base(self):
         tdSql.prepare()
         tdSql.execute('''create table stb(ts timestamp, col1 tinyint, col2 smallint, col3 int, col4 bigint, col5 tinyint unsigned, col6 smallint unsigned, 
@@ -69,8 +56,8 @@ class TDTestCase:
         tdSql.execute('drop database db')
     def top_check_stb_distribute(self):
         # prepare data for vgroup 4
-        dbname = self.get_long_name(length=10, mode="letters")
-        stbname = self.get_long_name(length=5, mode="letters")
+        dbname = tdCom.getLongName(10, "letters")
+        stbname = tdCom.getLongName(5, "letters")
         tdSql.execute(f"create database if not exists {dbname} vgroups 2")
         tdSql.execute(f'use {dbname}')
         # build 20 child tables,every table insert 10 rows