1、 查询Departments表中的所有记录；
Use yggl;
Select * from departments;
2、 查询Employees表中员工的姓名，地址和电话；
Select name,address,phonenumber
From employees;
3、 查询Employees表中员工的部门号和性别，要求消除重复行；
Select distinct departmentid,sex
From employees;
4、 查询EmployeeID为000001的员工地址和电话，要求显示列名为address、telephone；
Select address as address,phonenumber as telephone
From employees
Where employeeid = ‘000001’;
5、 查询Employees表中员工的姓名和性别，要求性别为1时显示为“男”，为0时显示为“女”；
Select name,
Case
When sex=1 then ‘男’
When sex=0 then ‘女’
End as sex
From employees;
6、 计算Salary表中所有员工收入的平均值、最大值和最小值；
Select avg(income),max(income),min(income)
From salary;
7、 计算所有员工的总支出；
Select sum(outcome) as ‘总支出’
From salary;
8、 计算员工总数；
Select count(*) as ‘员工总数’
From employees;
9、 显示女员工的地址和电话；
Select name as ‘姓名’,address as ‘地址’,phonenumber as ‘电话’
From employees
Where sex =0;
10、 查询月收入高于2000元的员工编号；
Select employeeid
From salary
Where income>2000;
11、 查询1970年以后出生的员工的姓名和地址；
Select name as’姓名’，address as ‘地址’
From employees
Where birthday >’197-12-31’;
12、 查询地址中含有“中山”的员工编号和部门号；
Select name as’姓名’，employeeid as ‘员工编号’,departmentid as ‘部门号’
From employees
Where address like ‘中山%’;
13、 查询员工编号中倒数第二个数字为0的姓名、地址和学历；
Select name,address,education
From employees
Where employeeid like ‘%0_’;
14、 找出所有收入在2000-3000元之间的员工编号和姓名；
Select name as ’姓名’，salary.employeeid as ‘员工编号’
From employees,salary
Where employees.employeeid=salary.employeeid
And income>2000 and income<3000;
15、 查询所有在部门“1”或“2” 工作的员工编号。
Select name as’姓名’，employeeid as ‘员工编号’
From employees
Where departmentid=1 or departmentid=2;
