题解 | #未完成试卷数大于1的有效用户#

select uid, count(*) - count(submit_time) as uncon, count(submit_time) as con, group_concat(distinct concat(date(start_time), ':', tag) separator ';') from exam_record join examination_info using (exam_id) where year(start_time) = 2021 group by uid having con >= 1 and uncon < 5 and uncon > 1 order by uncon desc