题解 | #获得积分最多的人(一)#

select t.name,t1.grade_num
from user t 
right join 
(
 select distinct user_id,sum(grade_num)over(partition by user_id) grade_num
 from grade_info
)t1
on t.id = t1.user_id
where t1.grade_num = (select
                      max(b.sum_num)
                      from(
                      select (sum(grade_num)over(partition by user_id)) sum_num 
                      from grade_info) b)
或
select t.name,t1.grade_num
from user t 
right join 
(
 select distinct user_id,sum(grade_num)over(partition by user_id) grade_num
 from grade_info
 order by 2 desc
 limit 1
)t1
on t.id = t1.user_id