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,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语句可以实现查询没有选修'C002'号课程的学生姓名。
A.
select sname from student, sc where student.sno=sc.sno and cno !='C002'
B.
select sname from student where sno not in (select sno from sc where cno='C002')
C.
select sname from student where exixts (select * from sc where student.sno=sc.sno and cno<>'C002')
D.
select sname from student where not exixts (select * from sc where student.sno=sc.sno and cno='C002')