在学生选课数据库S_T中有学生表student(sno,sname,ssex,sage,sdept),课程表course(cno,cname,cpno,ccredit)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,cpno是先行课号,ccredit是学分,grade是成绩。以下( )SQL语句可以实现查询没有选修'1'号课程的学生姓名。
选项:
A:select sname from student where not exists (select * from sc where student.sno=sc.sno and cno='1');
B:select sname from student, sc where student.sno=sc.sno and cno !='1';
C:select sname from student where sno not in (select sno from sc where cno='1');
D:select sname from student where exists (select * from sc where student.sno=sc.sno and cno<>'1')
发布时间:2024-03-30 10:04:50