第11題寫錯(cuò)了。應(yīng)該是:
select student.SId,student.Sname,b.avg
from student RIGHT JOIN
(select sid,AVG(score) as avg from sc
where sid in (select sid from sc where score<60 GROUP BY sid HAVING count(score)>1)
GROUP BY sid) b on student.sid=b.sid;
把條件中“不及格”改成小于80分建车,就會(huì)看到 平均分 不一樣了。
8fee0c253d12 評(píng)論自50道SQL練習(xí)題及答案與詳細(xì)分析