diff --git a/tests/system-test/2-query/Now.py b/tests/system-test/2-query/Now.py
new file mode 100644
index 0000000000..7f0e173439
--- /dev/null
+++ b/tests/system-test/2-query/Now.py
@@ -0,0 +1,310 @@
+
+
+from util.dnodes import *
+from util.log import *
+from util.sql import *
+from util.cases import *
+
+
+class TDTestCase:
+
+    def init(self, conn, logSql):
+        tdLog.debug(f"start to excute {__file__}")
+        tdSql.init(conn.cursor())
+
+    def run(self):  # sourcery skip: extract-duplicate-method
+        # for func now() , today(), timezone()
+        tdSql.prepare()
+        today_date = datetime.datetime.strptime(
+            datetime.datetime.now().strftime("%Y-%m-%d"), "%Y-%m-%d")
+
+        tdLog.printNoPrefix("==========step1:create tables==========")
+        tdSql.execute(
+            '''create table if not exists ntb
+            (ts timestamp, c1 int, c2 float,c3 double,c4 timestamp)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb
+            (ts timestamp, c1 int, c2 float,c3 double,c4 timestamp) tags(t0 int)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb_1 using stb tags(100)
+            '''
+        )
+        tdLog.printNoPrefix("==========step2:insert data into ntb==========")
+        tdSql.execute(
+            'insert into ntb values(now,1,1.55,100.555555,today())("2020-1-1 00:00:00",10,11.11,99.999999,now())(today(),3,3.333,333.333333,now())')
+        tdSql.execute(
+            'insert into stb_1 values(now,1,1.55,100.555555,today())("2020-1-1 00:00:00",10,11.11,99.999999,now())(today(),3,3.333,333.333333,now())')
+        tdLog.printNoPrefix("==========step2:query test of ntb ==========")
+
+        # test function now()
+        # ntable
+        tdSql.query("select now() from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1w from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1w from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1d from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1d from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1h from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1h from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1m from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1m from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1s from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1s from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1a from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1a from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1u from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1u from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1b from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1b from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1w from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1w from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1d from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1d from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1h from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1h from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1m from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1m from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1s from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1s from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1a from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1a from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1u from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1u from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1b from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1b from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select * from ntb where ts<now()")
+        tdSql.checkRows(3)
+        tdSql.checkData(1, 1, 3)
+        tdSql.query("select * from ntb where ts<=now()")
+        tdSql.checkRows(3)
+        tdSql.checkData(2, 1, 1)
+        tdSql.query("select c1 from ntb where ts=now()")
+        tdSql.checkRows(0)
+        tdSql.query("select * from ntb where ts>=now()")
+        tdSql.checkRows(0)
+        tdSql.query("select * from ntb where ts>now()")
+        tdSql.checkRows(0)
+        tdSql.query("select now() from ntb where ts=today()")
+        tdSql.checkRows(1)
+
+        # stable
+        tdSql.query("select now() from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1w from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1w from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1d from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1d from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1h from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1h from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1m from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1m from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1s from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1s from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1a from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1a from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1u from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1u from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1b from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1b from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1w from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1w from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1d from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1d from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1h from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1h from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1m from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1m from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1s from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1s from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1a from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1a from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1u from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1u from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1b from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1b from db.stb")
+        tdSql.checkRows(3)
+        # tdSql.query("select * from stb where ts<now()")
+        # tdSql.checkRows(3)
+        # tdSql.checkData(1,1,3)
+        # tdSql.query("select * from stb where ts<=now()")
+        # tdSql.checkRows(3)
+        # tdSql.checkData(2,1,1)
+        tdSql.query("select c1 from stb where ts=now()")
+        tdSql.checkRows(0)
+        # tdSql.query("select * from stb where ts>=now()")
+        # tdSql.checkRows(0)
+        # tdSql.query("select * from stb where ts>now()")
+        # tdSql.checkRows(0)
+        tdSql.query("select now() from stb where ts=today()")
+        tdSql.checkRows(1)
+
+        # table
+        tdSql.query("select now() from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1w from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1w from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1d from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1d from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1h from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1h from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1m from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1m from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1s from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1s from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1a from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1a from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1u from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1u from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1b from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() +1b from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1w from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1w from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1d from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1d from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1h from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1h from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1m from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1m from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1s from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1s from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1a from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1a from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1u from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1u from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1b from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select now() -1b from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select * from stb_1 where ts<now()")
+        tdSql.checkRows(3)
+        tdSql.checkData(1, 1, 3)
+        tdSql.query("select * from stb_1 where ts<=now()")
+        tdSql.checkRows(3)
+        tdSql.checkData(2, 1, 1)
+        tdSql.query("select c1 from stb_1 where ts=now()")
+        tdSql.checkRows(0)
+        tdSql.query("select * from stb_1 where ts>=now()")
+        tdSql.checkRows(0)
+        tdSql.query("select * from stb_1 where ts>now()")
+        tdSql.checkRows(0)
+
+        # tdSql.query("select * from stb_1 where ts<now")
+        # tdSql.checkRows(3)
+        # tdSql.checkData(1, 1, 3)
+        # tdSql.query("select * from stb_1 where ts<=now")
+        # tdSql.checkRows(3)
+        # tdSql.checkData(2, 1, 1)
+        # tdSql.query("select c1 from stb_1 where ts=now")
+        # tdSql.checkRows(0)
+        # tdSql.query("select * from stb_1 where ts>=now")
+        # tdSql.checkRows(0)
+        # tdSql.query("select * from stb_1 where ts>now")
+        # tdSql.checkRows(0)
+        
+        tdSql.query("select now() from stb_1 where ts=today()")
+        tdSql.checkRows(1)
+
+    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/To_iso8061.py b/tests/system-test/2-query/To_iso8061.py
new file mode 100644
index 0000000000..fca53572ca
--- /dev/null
+++ b/tests/system-test/2-query/To_iso8061.py
@@ -0,0 +1,78 @@
+from time import sleep
+
+from util.log import *
+from util.sql import *
+from util.cases import *
+
+
+
+
+class TDTestCase:
+
+    def init(self, conn, logSql):
+        tdLog.debug(f"start to excute {__file__}")
+        tdSql.init(conn.cursor())
+
+    def run(self):  # sourcery skip: extract-duplicate-method
+        tdSql.prepare()
+        # get system timezone
+        today_date = datetime.datetime.strptime(
+            datetime.datetime.now().strftime("%Y-%m-%d"), "%Y-%m-%d")
+        
+        tdLog.printNoPrefix("==========step1:create tables==========")
+        tdSql.execute(
+            '''create table if not exists ntb
+            (ts timestamp, c1 int, c2 float,c3 double,c4 timestamp)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb
+            (ts timestamp, c1 int, c2 float,c3 double,c4 timestamp) tags(t0 int)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb_1 using stb tags(100)
+            '''
+        )
+
+        tdLog.printNoPrefix("==========step2:insert data==========")
+        tdSql.execute('insert into ntb values(now,1,1.55,100.555555,today())("2020-1-1 00:00:00",10,11.11,99.999999,now())(today(),3,3.333,333.333333,now())')
+        tdSql.execute('insert into stb_1 values(now,1,1.55,100.555555,today())("2020-1-1 00:00:00",10,11.11,99.999999,now())(today(),3,3.333,333.333333,now())')
+
+        tdSql.query("select to_iso8601(ts) from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select c1 from ntb where ts = to_iso8601(1577808000000)")
+        tdSql.checkRows(1)
+        tdSql.checkData(0,0,10)
+        tdSql.query("select * from ntb where ts = to_iso8601(1577808000000)")
+        tdSql.checkRows(1)
+        tdSql.query("select to_iso8601(ts) from ntb where ts=today()")
+        tdSql.checkRows(1)
+        # tdSql.checkData(0,0,10)
+        for i in range(1,10):
+            tdSql.query("select to_iso8601(1) from ntb")
+            tdSql.checkData(0,0,"1970-01-01T08:00:01+0800")
+            i+=1
+            sleep(0.2)
+            tdSql.checkRows(3)
+        tdSql.query("select to_iso8601(ts) from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select to_iso8601(ts) from db.ntb")
+        
+        tdSql.query("select to_iso8601(today()) from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select to_iso8601(now()) from ntb")
+        tdSql.checkRows(3)
+        
+        tdSql.error("select to_iso8601(timezone()) from ntb")
+        tdSql.error("select to_iso8601('abc') from ntb")
+
+
+
+
+    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/Today.py b/tests/system-test/2-query/Today.py
new file mode 100644
index 0000000000..ad4e48bda5
--- /dev/null
+++ b/tests/system-test/2-query/Today.py
@@ -0,0 +1,318 @@
+
+
+from util.dnodes import *
+from util.log import *
+from util.sql import *
+from util.cases import *
+
+
+class TDTestCase:
+
+    def init(self, conn, logSql):
+        tdLog.debug(f"start to excute {__file__}")
+        tdSql.init(conn.cursor())
+
+    def run(self):  # sourcery skip: extract-duplicate-method
+        # for func now() , today(), timezone()
+        tdSql.prepare()
+        today_date = datetime.datetime.strptime(
+            datetime.datetime.now().strftime("%Y-%m-%d"), "%Y-%m-%d")
+
+        tdLog.printNoPrefix("==========step1:create tables==========")
+        tdSql.execute(
+            '''create table if not exists ntb
+            (ts timestamp, c1 int, c2 float,c3 double,c4 timestamp)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb
+            (ts timestamp, c1 int, c2 float,c3 double,c4 timestamp) tags(t0 int)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb_1 using stb tags(100)
+            '''
+        )
+        tdLog.printNoPrefix("==========step2:insert data into ntb==========")
+        tdSql.execute(
+            'insert into ntb values(now,1,1.55,100.555555,today())("2020-1-1 00:00:00",10,11.11,99.999999,now())(today(),3,3.333,333.333333,now())')
+        tdSql.execute(
+            'insert into stb_1 values(now,1,1.55,100.555555,today())("2020-1-1 00:00:00",10,11.11,99.999999,now())(today(),3,3.333,333.333333,now())')
+        tdLog.printNoPrefix("==========step2:query test of ntb ==========")
+
+        # test function today()
+        # normal table
+        tdSql.query("select today() from ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() +1w from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1w from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1d from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1d from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1h from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1h from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1m from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1m from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1s from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1s from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1a from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1a from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1u from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1u from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1b from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1b from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1w from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1w from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1d from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1d from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1h from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1h from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1m from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1m from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1s from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1s from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1a from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1a from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1u from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1u from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1b from ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1b from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.query("select * from ntb where ts=today()")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 1, 3)
+        tdSql.query("select * from ntb where ts<=today()")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 1, 10)
+        # for bug
+        # tdSql.query("select * from ntb where ts<today()")
+        # tdSql.checkRows(1)
+        tdSql.query("select * from ntb where ts>=today()")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 1, 3)
+        # tdSql.query("select * from ntb where ts>today()")
+        # tdSql.checkRows(1)
+        tdSql.query("select c4 from ntb where c4=today()")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() from ntb where ts<now()")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, str(today_date))
+
+        # stable
+        tdSql.query("select today() from stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() +1w from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1w from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1d from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1d from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1h from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1h from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1m from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1m from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1s from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1s from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1a from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1a from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1u from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1u from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1b from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1b from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1w from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1w from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1d from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1d from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1h from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1h from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1m from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1m from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1s from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1s from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1a from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1a from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1u from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1u from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1b from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1b from db.stb")
+        tdSql.checkRows(3)
+        tdSql.query("select ts from stb where ts=today()")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select ts from stb where ts<=today()")
+        tdSql.checkRows(2)
+
+        # 
+        # tdSql.query("select * from ntb where ts<today()")
+        # tdSql.checkRows(1)
+        # tdSql.query("select * from stb where ts>=today()")
+        # tdSql.checkRows(2)
+        # tdSql.query("select * from ntb where ts>today()")
+        # tdSql.checkRows(1)
+        tdSql.query("select c4 from stb where c4=today()")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() from stb where ts<now()")
+        tdSql.checkRows(3)
+
+        # table
+        tdSql.query("select today() from stb_1")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select today() +1w from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1w from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1d from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1d from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1h from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1h from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1m from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1m from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1s from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1s from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1a from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1a from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1u from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1u from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1b from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() +1b from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1w from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1w from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1d from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1d from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1h from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1h from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1m from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1m from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1s from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1s from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1a from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1a from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1u from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1u from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1b from stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select today() -1b from db.stb_1")
+        tdSql.checkRows(3)
+        tdSql.query("select ts from stb_1 where ts=today()")
+        tdSql.checkRows(1)
+        tdSql.checkData(0, 0, str(today_date))
+        tdSql.query("select ts from stb_1 where ts<=today()")
+        tdSql.checkRows(2)
+        # for bug
+        tdSql.query("select * from ntb where ts<today()")
+        tdSql.checkRows(1)
+        tdSql.checkData(0,0,"2020-1-1 00:00:00")
+        tdSql.query("select * from stb_1 where ts>=today()")
+        tdSql.checkRows(2)
+        tdSql.query("select * from ntb where ts>today()")
+        tdSql.checkRows(1)
+        tdSql.query("select c4 from stb_1 where c4=today()")
+        tdSql.checkRows(1)
+        tdSql.query("select today() from stb_1 where ts<now()")
+        tdSql.checkRows(3)
+
+    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/timezone.py b/tests/system-test/2-query/timezone.py
new file mode 100644
index 0000000000..a273b1c0f8
--- /dev/null
+++ b/tests/system-test/2-query/timezone.py
@@ -0,0 +1,83 @@
+
+from util.log import *
+from util.sql import *
+from util.cases import *
+
+import os
+
+
+class TDTestCase:
+
+    def init(self, conn, logSql):
+        tdLog.debug(f"start to excute {__file__}")
+        tdSql.init(conn.cursor())
+
+    def run(self):  # sourcery skip: extract-duplicate-method
+        tdSql.prepare()
+        # get system timezone
+        time_zone = os.popen('timedatectl | grep zone').read(
+        ).strip().split(':')[1].lstrip()
+
+        tdLog.printNoPrefix("==========step1:create tables==========")
+        tdSql.execute(
+            '''create table if not exists ntb
+            (ts timestamp, c1 int, c2 float,c3 double)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb
+            (ts timestamp, c1 int, c2 float,c3 double) tags(t0 int)
+            '''
+        )
+        tdSql.execute(
+            '''create table if not exists stb_1 using stb tags(100)
+            '''
+        )
+
+        tdLog.printNoPrefix("==========step2:insert data==========")
+        tdSql.execute(
+            "insert into ntb values(now,10,99.99,11.111111)(today(),100,11.111,22.222222)")
+        tdSql.execute(
+            "insert into stb_1 values(now,111,99.99,11.111111)(today(),1,11.111,22.222222)")
+
+        tdLog.printNoPrefix("==========step3:query data==========")
+        
+        tdSql.query("select timezone() from ntb")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, time_zone)
+            
+
+        
+        tdSql.query("select timezone() from db.ntb")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, time_zone)
+        
+        tdSql.query("select timezone() from stb")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, time_zone)
+        tdSql.query("select timezone() from db.stb")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, time_zone)
+
+        tdSql.query("select timezone() from stb_1")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, time_zone)
+        tdSql.query("select timezone() from db.stb_1 ")
+        tdSql.checkRows(2)
+        tdSql.checkData(0, 0, time_zone)
+
+        tdSql.error("select timezone(1) from ntb")
+        tdSql.error("select timezone(now()) from stb")
+
+        tdSql.query(f"select * from ntb where timezone()='{time_zone}'")
+        tdSql.checkRows(2)
+        tdSql.query("select timezone()+1 from ntb")
+        tdSql.checkRows(2)
+
+    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/fulltest.sh b/tests/system-test/fulltest.sh
index 2954358feb..9acf5c5246 100755
--- a/tests/system-test/fulltest.sh
+++ b/tests/system-test/fulltest.sh
@@ -4,4 +4,10 @@ set -e
 #python3 ./test.py -f 2-query/between.py
 #python3 ./test.py -f 2-query/distinct.py
 python3 ./test.py -f 2-query/varchar.py
+
+python3 ./test.py -f 2-query/timezone.py
+python3 ./test.py -f 2-query/Now.py
+python3 ./test.py -f 2-query/Today.py
+
 #python3 ./test.py -f 2-query/cast.py
+