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 (start_time, '%Y%m') month, round( count(distinct uid, day (start_time)) / count(distinct uid) , 2 ) avg_active_days, count(distinct uid) mau from exam_record where submit_time is not null and year (start_time) = '2021' group by month;