题解 | 得分不小于平均分的最低分

select
    min(score) min_score_over_avg
from
    exam_record er
    join examination_info ei on er.exam_id = ei.exam_id
where
    tag = 'SQL'
    and submit_time is not null
    and score >= (
        select
            avg(score) 平均分数
        from
            exam_record er
            join examination_info ei on er.exam_id = ei.exam_id
        where
            tag = 'SQL'
            and submit_time is not null
    )