oracle over应用！ 在线等

[给力地板油]

分组中取最大的值(max) 并取这个最大的值的ID 一起显示出来


select max(V4MAXSPEED),ID from t_anerecord group by atid


在这个基础上怎么改呢 请思路

[ssqtjffcu]

select max(V4MAXSPEED) over(partition by atid), ID from t_anerecord

[xpingping]

select ID,V4MAXSPEED from (
select row_number()over(partition by atid order by V4MAXSPEED desc) rn, 
ID,
V4MAXSPEED  
from t_anerecord )
where rn=1

[给力地板油]

[Quote=引用 1 楼 的回复:]
select max(V4MAXSPEED) over(partition by atid), ID from t_anerecord
[/Quote]


select max(V4MAXSPEED) over(partition by atid order by V4MAXSPEED desc), ID from t_anerecord group by atid


为什么不是 group by 语句呢 如何在分组的基础上 找出最大值和 该最大值这行的信息呢

[大明湖畔_帅锅]

[Quote=引用 3 楼 的回复:]
select max(V4MAXSPEED) over(partition by atid order by V4MAXSPEED desc), ID from t_anerecord group by atid


为什么不是 group by 语句呢 如何在分组的基础上 找出最大值和 该最大值这行的信息呢
[/Quote]

partition by也是分组 这个相当于group by

2L的结果应该是对的 可以参考下 分组倒序排列取第一个 就是每组的最大值

[larrychen_bmw]

“分组中取最大的值(max) 并取这个最大的值的ID 一起显示出来”

理解起来是要找t_anerecord 中最大值的那行记录啊，

select V4MAXSPEED, id
  from (select V4MAXSPEED, ID from t_anerecord order by V4MAXSPEED desc)
 where rownum = 1