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