题解 | #获得积分最多的人(二)#

# 将两表连接起来，保留需要的字段
# 挑选出增加积分最多的用户
select g1.user_id,u1.name,sum(g1.grade_num) as grade_sum from 
grade_info as g1 left join user as u1 
on g1.user_id = u1.id 
where g1.user_id in (
# 找出增加积分最多的用户
select t2.user_id from (
select t1.user_id,DENSE_RANK() over(order by t1.grade_sum_1 desc) as rank_sum 
from (
select g2.user_id,sum(g2.grade_num) as grade_sum_1 from 
grade_info as g2 group by g2.user_id ) t1 ) t2 
where t2.rank_sum = 1 ) 
group by g1.user_id 
order by g1.user_id