在数据库中，以Student Course 和sc 表为基础完成以下视图定义:
1.定义计算机系学生基本情况视图V_Computer；
create view V_Computer
as
select *
from student
where sdept='CS';
将Student Course 和sc表中学生的学号，姓名，课程号，课程名，成绩定义为视图V_S_C_G
create view V_S_C_G
as
select distinct student.sno,sname,course.cno,cname
from student,sc,course
where student.sno=sc.sno and course.cno=sc.cno;
3. 将各系学生人数，平均年龄定义为视图V_NUM_AVG
create view V_NUM_AVG(xi,sums,asage)
as
select sdept,count(distinct sno),avg(sage)
from student
group by sdept;
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4.将各位学生选修课程的门数及平均成绩定义为视图V_AVG_S_G
create view V_AVG_S_G(sno,sums,avggrade)
as
select sno,count(distinct cno),avg(grade)
from sc
group by sno;
5. 各门课程的选修人数及平均成绩定义为视图V_AVG_C_G
create view V_VAG_C_G(cno,sums,average)
as
select cno,count(distinct sno),avg(grade)
from sc
group by cno;