查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；

select Student.S#,Student.Sname
from Student,SC
where Student.S#=SC.S# and SC.C#='001′and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002′);