select Student.S#,Student.Sname
from Student,SC
where Student.S#=SC.S#
group by Student.S#,Student.Sname having count(C#) <(select count(C#) from Course);

select Student.S#,Student.Sname
from Student,SC
where Student.S#=SC.S#
group by Student.S#,Student.Sname having count(C#) <(select count(C#) from Course);