题解 | 计算用户的平均次日留存率
计算用户的平均次日留存率
https://www.nowcoder.com/practice/126083961ae0415fbde061d7ebbde453
select
count(qpd2.date)/count(qpd1.date) avg_ret
from
(
select distinct
device_id,
date from question_practice_detail
) qpd1
left join (
select distinct
device_id,
date from question_practice_detail
) qpd2 on qpd1.device_id = qpd2.device_id
and qpd2.date = date_add(qpd1.date, interval 1 day)
