题解 | 得分不小于平均分的最低分

select
    min(score) as min_score_over_avg
from exam_record 
inner join examination_info
using(exam_id)
where tag="SQL"  and score is not null 
and score >=
(select avg(score) from exam_record where 
exam_id in (select exam_id from examination_info where tag="SQL") and score is not null)