MySQL 第6章 多表查询的课后习题

1.显示所有员工的姓名，部门号和部门名称。

SELECT e.last_name,e.department_id, d.department_name
FROM employees e LEFT OUTER JOIN departments d
ON e.`department_id` = d.`department_id`;

2.查询90号部门员工的job_id和90号部门的location_id

SELECT d.department_id,e.job_id,d.location_id,e.department_id
FROM  employees e JOIN departments d  
ON e.`department_id` = d.`department_id`
WHERE e.`department_id` = 90;

3.选择所有有奖金的员工的 last_name , department_name , location_id , city

SELECT e.last_name ,d.department_name , d.location_id, city 
FROM employees e 
LEFT OUTER JOIN departments d
ON e.`department_id` = d.`department_id`
LEFT OUTER JOIN locations l
ON d.`location_id` = l.`location_id`
WHERE commission_pct IS NOT NULL;

4.选择city在Toronto工作的员工的 last_name , job_id , department_id , department_name

SELECT  e.last_name , e.job_id , e.department_id , d.department_name 
FROM employees e
JOIN departments d
ON e.`department_id`=d.`department_id`
JOIN locations l
ON l.`location_id`= d.`location_id`
WHERE l.`city` = 'Toronto';

5.查询员工所在的部门名称、部门地址、姓名、工作、工资，其中员工所在部门的部门名称为’Executive’

SELECT e.last_name,e.job_id,e.salary,e.department_id,d.department_name,d.location_id,l.street_address
FROM employees e
join departments d
on e.`department_id` = d.`department_id`
join locations l
on d.`location_id`= l.`location_id`
WHERE d.`department_name` = 'Executive'

6.选择指定员工的姓名，员工号，以及他的管理者的姓名和员工号，结果类似于下面的格式

employees Emp# manager Mgr#

kochhar 101 king 100

SELECT emp.last_name "employees",emp.employee_id "Emp#",mgr.last_name "manager ",mgr.employee_id "Mgr#"
FROM employees emp
LEFT OUTER JOIN employees mgr
ON emp.`manager_id` = mgr.`employee_id`;

7.查询哪些部门没有员工 (本题也可以是使用子查询)

select d.department_id
From departments d 
LEFT Join employees e
ON d.`department_id` = e.`department_id`
WHERE e.`department_id` IS NULL;

8. 查询哪个城市没有部门

SELECT l.location_id
FROM locations l
left join departments d
on l.`location_id` = d.`location_id`
WHERE d.`location_id` IS NULL;

9. 查询部门名为 Sales 或 IT 的员工信息

SELECT e.employee_id,e.last_name,d.department_name
FROM employees e
JOIN departments d
ON e.`department_id`=d.`department_id`
WHERE d.`department_name` = "Sales" 
OR d.`department_name` = "IT";

OR

SELECT e.employee_id,e.last_name,d.department_name
FROM employees e
JOIN departments d
ON e.`department_id`=d.`department_id`
WHERE d.`department_name` in ("Sales","IT");