这题没有写出来 参考大佬的
select min(er.score) as min_score_over_avg
from exam_record er join examination_info ei
on er.exam_id = ei.exam_id
where ei.tag = 'SQL'
and score >= (select avg(er2.score)
from exam_record er2
join examination_info ei2
on er2.exam_id = ei2.exam_id
where tag = 'SQL'
)