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 month,round(sum(num_day)/count(uid),2) avg_active_days,round(count(distinct uid),2) mau
from
(SELECT month,uid,count(distinct day) num_day from
(select concat('20210',month(start_time)) month,date(start_time) day,uid from exam_record
where year(start_time) = '2021' and submit_time is not null) a
group by month,uid) b
group by month;
