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(间隔天数)/count(`date`),4) avg_ret from( select device_id,`date`, if(datediff(`date`,lag(`date`) over(partition by device_id order by `date`))=1,1,null) 间隔天数 from question_practice_detail group by device_id,`date` ) as 计算间隔天数 ;