题解 | #牛客每个人最近的登录日期(五)#
牛客每个人最近的登录日期(五)
https://www.nowcoder.com/practice/ea0c56cd700344b590182aad03cc61b8
select t0.date,
ifnull(round(count(distinct t2.user_id)/(count(t1.user_id)),3),0)
from
(
select date
from login
group by date
) t0
left join
(
select user_id,min(date) as date
from login
group by user_id
)t1
on t0.date=t1.date
left join login as t2
on t1.user_id=t2.user_id and datediff(t2.date,t1.date)=1
group by t0.date
不停反思
