29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select tname,prof from teacher where depart = '计算机系' and prof not in (
select prof from teacher where depart = '电子工程系'）
30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
select * from score a where cno = '3-105' and a.degree>(
select b.degree from score b where cno = '3-245'and a.sno=b.sno)