add to_unixtimestamp case

tests/system-test/2-query/To_unixtimestamp.py

+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()
+        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==========")
+        
+
+
+
+
+
+
+
+
+
+        
+
+
+    def stop(self):
+        tdSql.close()
+        tdLog.success(f"{__file__} successfully executed")
+
+tdCases.addLinux(__file__, TDTestCase())
+tdCases.addWindows(__file__, TDTestCase())
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