题解 | #分别满足两个活动的人#

select distinct uid,'activity1' activity
from examination_info
left join exam_record
using(exam_id)
group by uid
having min(score)>=85
union all
select distinct uid,'activity2' activity
from examination_info
left join exam_record
using(exam_id)
where difficulty='hard'
and timestampdiff(second,start_time,submit_time)<=duration*30
and score>80
order by uid,activity