题解 | #每个6/7级用户活跃情况#
每个6/7级用户活跃情况
https://www.nowcoder.com/practice/a32c7c8590324c96950417c57fa6ecd1
select uid,count(distinct concat(year(time),month(time)) ) act_month_total,count(distinct if(year(time) = '2021',time,null)) act_days_2021, count(distinct if(rc = 1 and year(time) = '2021',time,null)) act_days_2021_exam,count(distinct if( rc = 2 and year(time) = '2021',time,null)) act_days_2021_question from ( (select a.uid,date(b.start_time) time,1 rc from user_info a left join exam_record b on a.uid = b.uid where level = 6 or level = 7) union all (select a.uid,date(c.submit_time),2 rc from user_info a left join practice_record c on a.uid = c.uid where level = 6 or level = 7) ) d group by uid order by act_month_total desc,act_days_2021 desc;
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