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) as avg_ret
from (
select distinct device_id,date from question_practice_detail) q1
left join
(select distinct device_id,date from question_practice_detail) q2
on q1.device_id = q2.device_id
and q2.date =date_add(q1.date ,interval 1 day)