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(q2.device_id)/count(q1.device_id) avg_ret
from (
select distinct device_id,date
from question_practice_detail
) as q1 left join (
select distinct device_id, date
from question_practice_detail
) as q2 on q1.device_id=q2.device_id and datediff(q2.date,q1.date)=1