题解 | #每个题目和每份试卷被作答的人数和次数#

还有一种方法就是要不你就每个表加一个标记字段，比如A表增加一列rk 全为2，B表增加一列rk全为1，然后子查询再按rk字段，uv字段，pv字段再排

(
    select
        a.exam_id as tid,
        count(distinct a.uid) as uv,
        count(1) as pv
    from
        exam_record a
    group by
        a.exam_id
    order by
        uv desc,
        pv desc
    limit
        99999
)
union
(
    select
        a.question_id as tid,
        count(distinct a.uid) as uv,
        count(1) as pv
    from
        practice_record a
    group by
        a.question_id
    order by
        uv desc,
        pv desc
    limit
        9999
)