select code,time from ( select code,time,row_number()over(partition by code,trunc(time) order by time desc) rn )where rn=1 order by code,time
select code,time from ( select code,time,row_number()over(partition by code,trunc(time) order by time desc) rn from T )where rn=1 order by code,time 上面把from丢了,修正下
from (
select code,time,row_number()over(partition by code,trunc(time) order by time desc) rn
)where rn=1
order by code,time
from (
select code,time,row_number()over(partition by code,trunc(time) order by time desc) rn
from T
)where rn=1
order by code,time
上面把from丢了,修正下
想在优化一下,rn能不能计数 一个月出现的次数
顺便版主QQ是多少啊 工作中可能还有很多问题需要请教