题解 | 牛客每个人最近的登录日期(五)

select distinct
    date,
    round(if (p is null, 0, p), 3)
from
    login login1
    left join (
        select
            fdate,
            count(date) / count(fdate) p
        from
            (
                select
                    user_id,
                    min(date) fdate,
                    date_add(min(date), interval 1 day) sdate
                from
                    login
                group by
                    user_id
            ) as t1
            left join login on t1.user_id = login.user_id
            and t1.sdate = login.date
        group by
            fdate
    ) as t2 on login1.date = t2.fdate
order by
    date

表连接加到厌倦，先想办法算出p，然后连接日期就好了