select uid,sum(if(submit_time is null,1,0)) as ncnt, count(submit_time) as cnt , GROUP_CONCAT(distinct date(start_time),":",tag order by date(start_time),tag separator ';') from exam_record join examination_info ei on exam_record.exam_id = ei.exam_id where year(start_time) = 2021 group by uid havin...