top1 有多个，limit 1 不适用 rank()over()
获得积分最多的人(二)
https://www.nowcoder.com/practice/b6248d075d2d4213948b2e768080dc92
with t as(
select
distinct id,
name,
sum(grade_num) over(partition by user_id) grade_num
from user u
right join grade_info g on u.id=g.user_id
),
t1 as(
select
id,name,grade_num,
dense_rank() over(order by grade_num desc) r
from t
)
select
id,
name,
grade_num
from t1
where r=1
