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 * from (select exam_id as tid, count(distinct uid) uv, count(exam_id) pv from exam_record group by tid order by uv desc, pv desc)t1 union all select * from (select question_id as tid, count(distinct uid) uv, count(submit_time) pv from practice_record group by tid order by uv desc, pv desc)t2; order by在union中不起作用，必须放到子句中去
，这个代码不商用是没问题的