题解 | #未完成试卷数大于1的有效用户#

select uid,
        count(start_time)-count(submit_time) incomplete_cnt,
        count(submit_time) complete_cnt,
        group_concat(distinct concat(date(start_time),':',tag) order by  concat(date(start_time),':',tag) separator';')
from exam_record e1
left join examination_info e2 on e1.exam_id=e2.exam_id
where year(start_time)=2021
group by uid
having count(submit_time)>=1
        and count(start_time)-count(submit_time)<5
        and count(start_time)-count(submit_time)>1
order by count(start_time)-count(submit_time) desc;