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(t.date2)/count(1) from ( select distinct o.device_id,o.date date1,o1.date date2 from question_practice_detail o left join ( select distinct o2.device_id,o2.date from question_practice_detail o2 )o1 on o1.device_id =o.device_id and datediff (o.date ,o1.date ) =1 ) t