diff --git a/tests/system-test/2-query/To_iso8061.py b/tests/system-test/2-query/To_iso8061.py
index fca53572ca..86322ed076 100644
--- a/tests/system-test/2-query/To_iso8061.py
+++ b/tests/system-test/2-query/To_iso8061.py
@@ -67,6 +67,75 @@ class TDTestCase:
         tdSql.error("select to_iso8601(timezone()) from ntb")
         tdSql.error("select to_iso8601('abc') from ntb")
 
+        tdSql.query("select to_iso8601(today()) *null from ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) +null from ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) -null from ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) /null from ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+
+        tdSql.query("select to_iso8601(today()) *null from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) +null from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) -null from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) /null from db.ntb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+
+
+
+
+        tdSql.query("select to_iso8601(now) from stb")
+        tdSql.query("select to_iso8601(now()) from stb")
+        tdSql.checkRows(3)
+        for i in range(1,10):
+            tdSql.query("select to_iso8601(1) from stb")
+            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 stb")
+        tdSql.checkRows(3)
+        tdSql.query("select to_iso8601(ts)+1 from stb")
+        tdSql.checkRows(3)
+        tdSql.query("select to_iso8601(ts)+'a' from stb ")
+        tdSql.checkRows(3)
+        # tdSql.query()
+        tdSql.query("select to_iso8601(today()) *null from stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) +null from stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) -null from stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) /null from stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) *null from db.stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) +null from db.stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) -null from db.stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)
+        tdSql.query("select to_iso8601(today()) /null from db.stb")
+        tdSql.checkRows(3)
+        tdSql.checkData(0,0,None)