SQL 开窗函数+表子查询练习题

统计每天回流玩家的数量，（连续7天不登录，7天后登录算回流玩家）

login_date和uid为联合主键

select *,count(1) as 一天内回流玩家的数量
from(
select *,
lag(login_date,1) over(partition by uid order by login_date asc) as 上次登录日期,
timestampdiff(day,lag(login_date,1) over(partition by uid order by login_date asc),login_date) as 登录间隔天数 
from login_user) as t
where 登录间隔天数>7
group by login_date;