sql删除语句的写法

sql删除语句的写法

1、多表级联删除：

---DELETE---

DELETE from a_msg_push,a_announcement

using a_msg_push,a_announcement

where  a_msg_push.announcement_id=a_announcement.id and a_announcement.Create_time<'2014-11-19 23:59:59';

2、子查询删除：

-----------delete--------

DELETE From  t_repeat  where t_repeat.id in(

SELECT tb.id from (

SELECT *  from t_repeat   t 

where 

1=1

and 

(t.cid,t.uid ) in (select t1.cid,t1.uid from t_repeat t1 group by t1.cid,t1.uid having count(*) > 1) 

and 

t.id  not in (select min(t2.id) from t_repeat t2 group by t2.cid,t2.uid having count(*)>1) 

) as tb )

3、子表删除：

-----------delete--------

DELETE From  t_repeat  where t_repeat.id  not in

( 

   SELECT tb.id from(

select  a.id from t_repeat a where a.id =(

select   max(b.id) from t_repeat b where a.cid=b.cid and a.uid=b.uid

) 

   )as tb

)