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)
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
q1.date = date_sub(q2.date, interval 1 day)