from user u
right join (
select *, sum(grade_num) over(partition by user_id) grade_sum
from grade_info
order by grade_sum desc
limit 1
) x on x.user_id = u.id
from user u
right join (
select *, sum(grade_num) over(partition by user_id) grade_sum
from grade_info
order by grade_sum desc
limit 1
) x on x.user_id = u.id