题解 | #得分不小于平均分的最低分#

select score from exam_record
where score>=
(
select 
    avg(score)
from 
    exam_record e1
join 
    examination_info e2 
on 
    e1.exam_id=e2.exam_id
and 
    e2.tag='SQL'
group by 
    e2.tag
)
and exam_id in(select exam_id from examination_info where tag='SQL')
order by score
limit 1;