《sql 数据库上机实验三》.doc
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实目的：
掌握数据查询操作。
内容：1）2) 对各表中的数据进行不同条件的查询；
附录： 语句清单
--sql 查询实验三代码
--------1
select student.*,sc.cno,sc.grade ----左外连接(显性连接)
from student left join sc on student.sno=sc.sno
/*
select student.*,sc.cno,sc.grade
from student inner join sc ----内连接法（显性连接）
on student.sno=sc.sno
*/
/*
select student.*,sc.cno,sc.grade ----------隐性连接
from student,sc
where student.sno=sc.sno
*/
select first.cname,first.cpno,second.cno
from course first,course second ----------2
where first.cpno=second.cno
select student.*,sc.* ---------------3
from student right join sc on student.sno=sc.sno
select student.sno,sname
from student,sc,(select student.sno
from student,sc -----4 导出表的使用
where sc.sno=student.sno and cno=2
group by student.sno)as result(sno)
where student.sno=sc.sno and cno=3
group by student.sno,student.sname
select student.sno,sname
from student,sc as x --------4法二
where student.sno=x.sno and cno=2 and exists(select student.sno
from student,sc as y
where cno=3 and exists(select *
from student,sc as z
where z.sno=y.sno and z.sno=x.sno))
select student.sno,sname
from student,sc as x,sc as y ------4法三
where student.sno=x.sno and x.sno=y.sno and x.cno=2 and y.cno=3
select *
from student as x,student y --------5
where x.sname=刘晨 and x.sage=y.sage
select sname,sage
from student,sc,course -----------6
where student.sno=sc.sno and sc.cno=course.cno and course.cname=数据库
select sname
from student
where sageany(select sage
from student ----------7
where sdept=is
) and sdept is
select sname
from student
where sageall(select sage ------8
from student
where sdept=is)
and sdept is
select sname
from student ------------9
where sno in(select sno
from sc
group by sno
having COUNT(*)=7)
select * --------------10
from stu
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