题解 | 牛客每个人最近的登录日期(三)

select round(sum(if(date_add(t.date,interval 1 day ) = l2.date ,1,0))/count(distinct t.user_id),3)as p
from (
    select  user_id,  min(date) as date
    from login
    group by user_id
     ) as t
join login l2
on t.user_id=l2.user_id

;