题解 | #获得积分最多的人(二)#

1.将grade_info表按照用户分数求和

select user_id,sum(grade_num) grades
from grade_info 
group by user_id; t2

2.与user表关联

select id,name,grades from 
t2 join user t1
on t1.id = t2.user_id; t3

3.给出排序（利用窗口函数）

select id,name,grades,rank() over(order by grades desc) rk
from t3；t4

4.输出最高

select id,name,grades from t4
where rk = 1

最终的sql

select id,name,grades from 
(select id,name,grades,rank() over(order by grades desc) rk
from (select id,name,grades from 
(select user_id,sum(grade_num) grades
from grade_info 
group by user_id)t2 join user t1
on t1.id = t2.user_id)t3)t4
where rk = 1