题解 | #平均活跃天数和月活人数#
平均活跃天数和月活人数
https://www.nowcoder.com/practice/9e2fb674b58b4f60ac765b7a37dde1b9
select date_format(temp.day, '%Y%m') as month, round(count(*) / count(distinct uid),2)as avg_active_days, count(distinct uid) mau from (select er.uid, date_format(start_time, '%Y-%m-%d') as day from exam_record er where date_format(er.start_time, '%Y%m') in (select date_format(start_time, '%Y%m') as month from exam_record er where er.score is not null and year(start_time) = '2021' group by month) and er.score is not null group by er.uid, day) as temp group by month;