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 (submit_time, '%Y%m') as month, round( count(distinct concat (date (submit_time), uid)) / count(distinct uid), 2 ) as avg_active_days, count(distinct uid) as mau from exam_record where year (submit_time) = 2021 group by month