Home Database Mysql Tutorial MySQL实现ORALCE的row_number()over(partition by xx)功能_MySQL

MySQL实现ORALCE的row_number()over(partition by xx)功能_MySQL

Jun 01, 2016 pm 01:07 PM

比如有个需求,要找出班级里每门课分数最高的学生(课程名称,分数,学生姓名),注意这里不是只取最高分,要把课程名称,分数,学生姓名都取出来!

在ORALCE里我们可以用ROW_NUMBER()OVER轻松实现,但是在mysql里就有点麻烦了,不过还是可以做的。

select course,score,name

from

(select

heyf_tmp.course,
heyf_tmp.score,
heyf_tmp.name,
@rownum:=@rownum+1,
if(@pdept=heyf_tmp.course,@rank:=@rank+1,@rank:=1) as rank,          -- 分组字段
@pdept:=heyf_tmp.course
from 
(select course,name,score
from temp_student_score
order by course,score desc                                           -- 分组字段,排序字段
) heyf_tmp ,

(select @rownum :=0,@pdept := null ,@rank:=0) a 

) a where rank=1

最后我们只用取出RANK=1的部分就可以了

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