题解 | #牛客每个人最近的登录日期(三)#
牛客每个人最近的登录日期(三)
http://www.nowcoder.com/practice/16d41af206cd4066a06a3a0aa585ad3d
select round(sum(t)/count(*),3) from (select user_id,if(FIND_IN_SET(date_add(min(date),interval 1 day),group_concat(date)),1,0) t from login group by user_id) a
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