SQL Server基础SQL脚本之Group By

--create table EmpTable

drop table EmpTable

CREATE TABLE EmpTable
(
    EmpName nchar(3),
    Region nvarchar(5),
    Department nvarchar(10),
    Salary money
)

--insert 6 records into the table

insert into EmpTable values
(N'李刚',N'山东',N'信息技术部',20000),
(N'赵云',N'广东',N'信息技术部',30000),
(N'周宇',N'山东',N'人力资源部',25000),
(N'李想',N'广东',N'人力资源部',40000),
(N'张涛',N'河北',N'信息技术部',50000),
(N'梁浩',N'山东',N'信息技术部',50000)

select * from EmpTable

-- 1).查看所有员工平均工资
select avg(Salary) as '平均工资' from EmpTable
-- 2).按照地区分组，查看每个地区的平均工资
select Region,avg(Salary) from EmpTable group by Region
select Region,sum(Salary) from EmpTable group by Region

select Region,avg(Salary) from EmpTable group by Region having avg(Salary)>40000
-- 3).按照部门分组，查看每个部门的平均工资
select Department,avg(Salary) from EmpTable group by Department
--4).同时按照地区和部门分组,显示如山东地区人力资源部的平均工资的信息
select Region,Department,avg(Salary) from EmpTable group by Region,Department
--5).同时按照地区和部门、地区、部门分组
select Region,Department,avg(Salary) from EmpTable
group by
grouping sets
(
 (Region,Department), (Region), (Department)
)
--6).按照部门分组的同时显示总的平均
select Region,sum(Salary) from EmpTable group by Region
select sum(Salary) from EmpTable

select Region,sum(Salary) from EmpTable group by rollup(Region)
--Region
--不分组

select Region,Department,sum(Salary) from EmpTable group by rollup(Region,Department)
--Region,Department
--Region
--不分组

-- rollup(A,B,C)
-- A,B,C
-- A,B
-- A 
-- 不分组

--7).同时按照地区和部门分组时，同时显示地区平均，部门平均和总平均
select Region,Department,sum(Salary) from EmpTable group by cube(Region,Department)
--Region+Department
--Region
--Department
--不分组

--cube(A,B,C)
--A
--B
--C
--A,B
--A,C
--B,C
--A,B,C
--不分组
--周末了，加班的继续加班，休班的好好休息吧！