明确题意:

找到SQL试卷得分不小于该类试卷平均得分的用户最低得分


问题分解:

  • 找到SQL类试卷得分的平均分。
    • 试卷作答记录表关联试卷信息表:join using
    • 筛选试卷类别:where tag='SQL'
    • 取平均分:avg(score)
  • 找到分数不小于平均分的记录:where tag='SQL' and score>=(...)
  • 取最低分:min(score)

细节问题:

  • 表头重命名:as

完整代码:

select min(score) as min_score_over_avg
from exam_record
join examination_info using(exam_id)
where tag='SQL'
and score >= (
    select avg(score)
    from exam_record
    join examination_info using(exam_id)
    where tag='SQL'
)