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
根据示例数据，需要先换exam_id的结果排序，再按question_id的结果排序，然后再将两者合并
select tid, uv, pv from ( select exam_id as tid, count(distinct uid) as uv, count(*) as pv from exam_record group by exam_id order by uv desc, pv desc ) a union all select tid, uv, pv from ( select question_id as tid, count(distinct uid) as uv, count(*) as pv from practice_record group by question_id order by uv desc, pv desc) b
