题解 | #每个题目和每份试卷被作答的人数和次数#
每个题目和每份试卷被作答的人数和次数
https://www.nowcoder.com/practice/203d0aed8928429a8978185d9a03babc
(select exam_id as tid,count(distinct(uid)) as uv, count(exam_id) as pv from exam_record group by tid ) union (select question_id as tid,count(distinct(uid)) as uv,count(question_id) as pv from practice_record group by tid ) order by left(tid,1) desc,uv desc,pv desc