select date_format(submit_time,'%Y%m') as month, round(count(distinct uid,date_format(submit_time,'%Y%m%d'))/count(distinct uid),2) as avg_active_days, count(distinct uid) as mau from exam_record where start_time like'2021%' and submit_time is not null group by date_format(submit_time,'%Y%m'); 最大的收获...