题解 | #牛客每个人最近的登录日期(六)#

select u.name u_n, a.date, sum(b.number) ps_num
from passing_number a, passing_number b, user u
where a.date >= b.date and a.user_id = b.user_id and a.user_id = u.id
group by a.user_id, u_n, a.date
order by a.date, u_n