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(b.date)/count(a.date) as avg_ret from (select distinct device_id, date from question_practice_detail) as a left join(select distinct device_id,date from question_practice_detail) as b on a.device_id=b.device_id and date_add(a.date,interval 1 day)=b.date