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( distinct b.device_id,b.date)/count(distinct a.device_id,a.date) avg_ret from question_practice_detail a left join question_practice_detail b on a.device_id = b.device_id and (a.date =b.date+1 )#sql##sql练习日常#
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