1   create view IS_Student.note

create view IS_Student

as

select Sno,Sname,Sage,Sdept

 from student

where Sdept='IS'

select * from IS_student

2 .note

create view IS_S1(Sno,Sname,   Grade)

as

select student.Sno,  Sname,     Grade

 from student,             sc

where Sdept='IS' and Student.sno=sc.sno  and sc.cno='1'

select * from IS_s1

3  涉及    两个表  ---叙述清楚.note

create view IS_S1(Sno,Sname,   Grade)

as

select student.Sno,  Sname,     Grade

 from student,             sc

where Sdept='IS' and Student.sno=sc.sno  and sc.cno='1'

select * from IS_s1  

4  视图的视图.note

create view IS_S2

as

select Sno,  Sname,     Grade

 from IS_s1

where Grade>=90

select * from IS_s1  

5  带 表达式的    视图.note

create view BT_s(Sno, Sname, Sbirth)

as

select Sno,  Sname,     2016-Sage

 from  student

select * from BT_s

6 分组视图.note

create view S_G(Sno, Grade)

as

select Sno,  AVG(Grade)

 from  SC

group by sno

select * from S_G  

7.note

create view F_student(F_Sno, F_name,F_sex,F_age, F_dept)

as

select *

 from  student

where Ssex='女'

select * from F_student  

8 删除视图.note

drop view IS_s1