--------------------------视图-----------------------视图是一个虚拟表，数据来自于原表，原表的数据改变，视图也会改变select Student.Sno,sname,ssex,class,cno,degree from Student join Score on Student.Sno=Score.Sno --以下代码由系统自己生成，在左边的对象管理器中，右键视图-新建视图SELECT     dbo.Student.Sno AS Expr2, dbo.Student.Sname AS Expr3, dbo.Student.Ssex AS Expr4, dbo.Student.Sbirthday AS Expr5, dbo.Student.Class AS Expr6, dbo.Score.Cno AS Expr7,                       dbo.Score.Degree AS Expr8FROM         dbo.Student INNER JOIN                      dbo.Score ON dbo.Student.Sno = dbo.Score.Sno------------------------------------------用代码生成视图--只能有表连接 join on, 不能出现聚合函数，等等create view St_Scasselect Student.Sno,sname,ssex,class,cno,degree from Student join Score on Student.Sno=Score.Sno ----------查询视图select *from St_Sc-----------------------不用 join oncreate view sscasselect Student.Sno,Sname,Ssex,Sbirthday,Class,Score.Cno,Cname,Tno,Degree  from Student,Course,Score where Student.Sno=Score.Sno and Score.Cno=Course.Cno------------------使用 join oncreate view sssasselect Student.Sno,Sname,Ssex,Sbirthday,Class,Score.Cno,Cname,Tno,Degree from Score join Course on Score.Cno=Course.Cnojoin Student on Student.Sno=Score.Snoselect *from sscselect *from sss------------修改视图----需要重写，相当于删掉重建alter view sssasselect Student.Sno,Sname,Ssex,Class,Score.Cno,Cname,Tno,Degree from Score join Course on Score.Cno=Course.Cnojoin Student on Student.Sno=Score.Sno