题解 | #牛客每个人最近的登录日期(六)#

select u.name as u_n
        ,p.date as date
        ,sum(p.number)over(partition by u.name order by date)as ps_num
from passing_number p,user u
where p.user_id=u.id
order by p.date,u.name;

登录没有刷题的数据不需要输出，所以截至到某天指的是刷题表有记录的日期，没有用到登录表

窗口函数按姓名分区按日期排序计算累计数

select u.name as u_n
        ,p.date as date
        ,sum(p.number)over(partition by u.name order by date)as ps_num
from passing_number p,user u
where p.user_id=u.id
order by p.date,u.name;