delete event from event inner join vent t on t.sid = event.sid and t.id < event.id
delete from event as e where sid != (select min(sid) from event where sid=e.sid);. [align=center]====思想重于技巧==== [/align] . 贴子分数<20:对自已的问题不予重视。 贴子大量未结:对别人的回答不予尊重。 .
上面错了,重贴一下。delete from event as e where id != (select min(id) from event where sid=e.sid); ordelete from event where sid not in (select mid from (select sid ,min(id) as mid from event group by sid)). [align=center]====思想重于技巧==== [/align] . 贴子分数<20:对自已的问题不予重视。 贴子大量未结:对别人的回答不予尊重。 .
where sid != (select min(sid) from event where sid=e.sid);.
[align=center]==== 思想重于技巧 ====
[/align]
.
贴子分数<20:对自已的问题不予重视。
贴子大量未结:对别人的回答不予尊重。
.
where id != (select min(id) from event where sid=e.sid);
ordelete from event
where sid not in (select mid from (select sid ,min(id) as mid from event group by sid)).
[align=center]==== 思想重于技巧 ====
[/align]
.
贴子分数<20:对自已的问题不予重视。
贴子大量未结:对别人的回答不予尊重。
.
SQL 1992
MySQL 5.1 Reference Manual
ActiveX Data Objects 2.5 Reference 下载
数据库系统概论PPT.
[align=center]==== 思想重于技巧 ====
[/align]
.
贴子分数<20:对自已的问题不予重视。
贴子大量未结:对别人的回答不予尊重。
.
alter ignore table event add unique index idu_sid (sid);
alter table event drop index idu_sid;