计算用户次日留存率,首先附上完整的MySQL运行答案: select round(count(*)/(select count(distinct user_id) from login),3) from ( select user_id, min(`date`) `date` from login group by user_id ) a where (a.user_id, DATE_ADD(a.`date`,INTERVAL 1 DAY)) in (select user_id, `date` from login) 详解如下:① 首先,按user_id分组,获取每个用户的最早登陆日期。记作...