select * from log group by username order by logtime desc
select username,logtim,logcontent from ( select username,logtime,logcontent,dense_rank()over(partition by username order by logtime desc) rn from log ) where rn=1 order by username
3楼的sql语句看不是太懂,不过还是谢谢,我先看中不中 中就给分
某个时间段的就更简单了 select * from log where logtime between to_date('2009-8-1','yyyy-mm-dd') and to_date('2009-10-1','yyyy-mm-dd')
3楼的答案我试过了,可行,非常感谢,分给你了。 你能随便讲讲中间的子查询dense_rank()over(partition by username order by logtime desc) 是什么意思吗?
from
(
select username,logtime,logcontent,dense_rank()over(partition by username order by logtime desc) rn
from log
)
where rn=1
order by username
select * from log
where logtime between to_date('2009-8-1','yyyy-mm-dd') and to_date('2009-10-1','yyyy-mm-dd')
你能随便讲讲中间的子查询dense_rank()over(partition by username order by logtime desc)
是什么意思吗?