题解 | #牛客每个人最近的登录日期(三)#
牛客每个人最近的登录日期(三)
https://www.nowcoder.com/practice/16d41af206cd4066a06a3a0aa585ad3d
真的有这么丝滑吗
select round(count(t2.user_id)/count(t1.user_id),3) from
(select user_id,min(date) date from login
group by user_id) t1
left join
(select user_id,date from login) t2
on t1.user_id = t2.user_id and
t2.date = date_add(t1.date,interval 1 day)
