oracle数据库创建视图

6.创建一个名为 VW_DEPT_SUM 的视图，统计部门名字，人数，最小工资，
­­最大工资，平均工资...
create or replace view
VW_DEPT_SUM(DEPT_NAME,EMP_COUNT,MINSAL,MAXSAL,AVGSAL)
AS
SELECT d.dname,count(distinct e.empno),min(e.sal),max(e.sal),avg(e.sal)
from emp e inner join dept d on e.deptno=d.deptno
group by d.deptno;
­­7.创建一个统计大于各部门平均工资的雇员的姓名、工资、部门名、该部门平
­­均工资的视图 VW_EMP_AVG
create or replace view VW_EMP_AVG(empname,salary ,deptname,avgsalary)
as
select
e.ename,e.sal,d.dname,(select
round(avg(sal),2)
from
emp
where
deptno=d.deptno)
from emp e inner join dept d on e.deptno=d.deptno
where e.sal>(select avg(sal) from emp);
select * from vw_emp_avg;
/*若要创建一个统计大于本人所在部门平均工资的雇员的姓名、工资、部门名、
该部门平均工资的视图 VW_EMP_AVG01，
语句如下：*/
create or replace view VW_EMP_AVG01(empname,salary ,deptname,avgsalary)
as
select
e.ename,e.sal,d.dname,(select
round(avg(sal),2)
from
emp
where
deptno=e.deptno)
from emp e inner join dept d on e.deptno=d.deptno
where e.sal>(select avg(sal) from emp where deptno=e.deptno);
­­select * from vw_emp_avg01;