select uid,total-finish as nonfinish,finish,
group_concat(
distinct concat(t,':',tag) separator ';'
) as detail
from(
select distinct
a.uid,
date(a.start_time) as t,
b.tag,
count(a.start_time) over(partition by a.uid) as total,
count(a.submit_time) over(partition by a.uid) as finish
from exam_record a ,examination_info b
where a.exam_id=b.exam_id
and a.start_time like '2021%' )c
where total-finish>1 and total-finish<5 and finish>=1
group by uid,nonfinish,finish
order by nonfinish desc