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 round(count(id2) / count(id),4) avg_ret from ( select distinct device_id id,date from question_practice_detail ) qpd left join ( select distinct device_id id2,date from question_practice_detail ) q2 on qpd.id = q2.id2 and q2.date=date_add( qpd.date ,interval 1 day );