[讨论]学生问的一个SQL问题 Post By:2011/1/20 9:48:53 [显示全部帖子]
将小明的英语成绩改为所有人的英语平均成绩
update grade set grade=(select avg(grade) from grade inner join course on grade.cid=course.cid where title='英语') where sid=(select sid from student where name='小明') and cid=(select cid from course where title='英语')