比如，表：event（id int（10） auto_increment primary key，
sid int（10）not null，
detail text）
我想删除表event中sid重复的记录，请问有没有这样SQL语句？或是通过其它方法？
delete from event as e
where id != (select min(id) from event where sid=e.sid);
or
delete from event
where sid not in (select mid from (select sid ,min(id) as mid from event group by sid))
应该是有用的代码
alter ignore table event add unique index idu_sid (sid);
alter table event drop index idu_sid;
