test: fix TestIfFunctionWithNull (pingcap#44229) (pingcap#44238)

close pingcap#44226

expression/integration_test.go

@@ -7466,6 +7466,6 @@ func TestIfFunctionWithNull(t *testing.T) {
 	tk.MustExec("drop table if exists ordres;")
 	tk.MustExec("CREATE TABLE orders (id bigint(20) unsigned NOT NULL ,account_id bigint(20) unsigned NOT NULL DEFAULT '0' ,loan bigint(20) unsigned NOT NULL DEFAULT '0' ,stage_num int(20) unsigned NOT NULL DEFAULT '0' ,apply_time bigint(20) unsigned NOT NULL DEFAULT '0' ,PRIMARY KEY (id) /*T![clustered_index] CLUSTERED */,KEY idx_orders_account_id (account_id),KEY idx_orders_apply_time (apply_time));")
 	tk.MustExec("insert into orders values (20, 210802010000721168, 20000 , 2 , 1682484268727), (22, 210802010000721168, 35100 , 4 , 1650885615002);")
-	tk.MustQuery("select min(if(apply_to_now_days <= 30,loan,null)) as min, max(if(apply_to_now_days <= 720,loan,null)) as max from (select loan, datediff(from_unixtime(unix_timestamp() + 18000), from_unixtime(apply_time/1000 + 18000)) as apply_to_now_days from orders) t1;").Sort().Check(
+	tk.MustQuery("select min(if(apply_to_now_days <= 30,loan,null)) as min, max(if(apply_to_now_days <= 720,loan,null)) as max from (select loan, datediff(from_unixtime(unix_timestamp('2023-05-18 18:43:43') + 18000), from_unixtime(apply_time/1000 + 18000)) as apply_to_now_days from orders) t1;").Sort().Check(
 		testkit.Rows("20000 35100"))
 }