在学生选课数据库中有学生表student(sno,sname,ssex,sage,sdept),课程表course(cno,cname)及学生选课表sc(sno,cno,grade),其中sno是学号,sname是姓名,ssex是性别,sage是年龄,sdept是系别,cno是课程号,cname是课程名,grade是成绩。以下( )SQL语句可以实现查询“CS”系并且年龄超过20岁的学生姓名。
选项:
A:select sname from student where sdept=’CS‘exceptselect sname from student where sage<=20;
B:select sname from student where sdept=’CS‘intersectselect sname from student where sage>20;
C:select sname from student where sdept=’CS‘ and sage>20;
D:select sname from student where sdept=’CS‘unionselect sname from student where sage>20
发布时间:2024-05-07 19:29:30