求助一句Delete语句的问题

[HarleyTung]

delete item where id not in(select max(id) from item group by cast(link as varchar(8000)))
这句是我的语句,可是item表数据量很大后查询速度就很慢，item表有6万条数据，执行完这句要40秒。

然后我就
delete item where id not in(select max(id) from item group by cast(link as varchar(8000))) and DATEDIFF(day,datetime,getdate())=0
这句目的就是想删除今天重复的数据，可是还是很慢，请问有什么办法可以变快吗？谢谢！

[火星求索]

up

[HarleyTung]

求助，谢谢！

[Limpire]

--try
delete item where id not in (select max(id) from item group by link) and DATEDIFF(day,datetime,getdate())=0

--try
delete item where id not in (select max(id) from item where DATEDIFF(day,datetime,getdate())=0 group by link) and DATEDIFF(day,datetime,getdate())=0

[HarleyTung]

非常感谢，delete item where id not in (select max(id) from item where DATEDIFF(day,datetime,getdate())=0 group by link) and DATEDIFF(day,datetime,getdate())=0
1秒都不到。呵呵