SQL165大厂面试真题
统计新用户次日留存率
select t1.dt, round(count(t2.uid)/count(t1.uid), 2)uv_rate from
(
select uid, min(date(in_time))dt from tb_user_log
group by uid
)as t1 left join
(
select uid, date(in_time)dt from tb_user_log union
select uid, date(out_time) from tb_user_log
)as t2
on t1.uid = t2.uid and t1.dt = date_sub(t2.dt, interval 1 day)
where date_format(t1.dt, '%Y-%m') = '2021-11'
group by t1.dt
order by t1.dt
#春招提前批,你开始投了吗#