题解 | #分别满足两个活动的人#

```select
    uid,
    'activity1' activity
from exam_record
where  year(start_time)
group by uid
having min(score)>=85
union 
select
    uid,
    'activity2' activity
from exam_record
left join examination_info using(exam_id)
where timestampdiff(minute,start_time,submit_time)< duration/2
    and score>80
    and difficulty='hard'
    and year(start_time)
group by uid   

order by uid
不懂问我