select * from byw_expo t1 where not exists (select 1 from byw_expo where uid = t1.uid and dabtime > t1.dabtime)
--try: select A.* from byw_expo A inner join (select uid,max([dabtime]) as [datetime] from byw_expo group by uid) B on A.uid=B.uid and A.[datetime]=B.[datetime]
有重复的?那就是说对于同一个用户,dabtime也有可能重复.那这样写:select * from byw_expo t1 where bid = (select top 1 bid from byw_expo where uid = t1.uid order by dabtime desc)
select uid,dabtime,btitle from byw_expo group by uid,btitle having dabtime=max(dabtime)
select uid,dabtime,btitle,max(dabtime) from byw_expo group by uid,btitle
where dabtime in(SELECT max(dabtime) from byw_expogroup by uid)
where not exists (select 1 from byw_expo where uid = t1.uid and dabtime > t1.dabtime)
select A.* from byw_expo A
inner join
(select uid,max([dabtime]) as [datetime] from byw_expo group by uid) B
on A.uid=B.uid and A.[datetime]=B.[datetime]
where bid = (select top 1 bid from byw_expo where uid = t1.uid order by dabtime desc)