题解 | #近三个月未完成试卷数为0的用户完成情况#

select
    uid,
    count(submit_time) as exam_complete_cnt
from
    (
        select
            uid,
            start_time,
            submit_time,
            dense_rank() over (
                partition by
                    uid
                order by
                    date_format (start_time, '%Y%m') desc
            ) as ranking
        from
            exam_record
    ) t1
where
    ranking <= 3
group by
    uid
having
    count(start_time) = count(submit_time)
order by exam_complete_cnt desc, uid desc