6.MYSQL-DQL查询语言学习-连接查询-SQL92标准

测试题：

#1.显示所有员工姓名，部门号和部门名称
SELECT
	last_name,
	E.department_id,
	department_name 
FROM
	employees E,
	departments D 
WHERE
	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
	job_id,
	location_id 
FROM
	employees E,
	departments D 
WHERE
	E.department_id = D.department_id 
	AND E.department_id = 90;

#3.选择所有有奖金的员工的last_name,department_name,location_id,city
SELECT
	last_name,
	department_name,
	L.location_id,
	city 
FROM
	employees E,
	departments D,
	locations L 
WHERE
	E.department_id = D.department_id 
	AND D.location_id = L.location_id 
	AND 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
	last_name,
	job_id,
	D.department_id,
	department_name,
	city 
FROM
	employees E,
	departments D,
	locations L 
WHERE
	E.department_id = D.department_id 
	AND L.city = 'Toronto';

#5.查询每个工种、每个部门的部门名、工种名和最低工资
SELECT
	MIN( salary ),
	J.job_id,
	department_name,
	job_title 
FROM
	employees E,
	departments D,
	jobs J 
WHERE
	D.department_id = E.department_id 
	AND E.job_id = J.job_id 
GROUP BY
	E.job_id,
	E.department_id;
#6.查询每个国家下的部门个数大于2的国家编号
SELECT
	COUNT( E.department_id ),
	country_id,
	D.location_id 
FROM
	employees E,
	departments D,
	locations L 
WHERE
	E.department_id = D.department_id 
	AND D.location_id = L.location_id 
GROUP BY
	country_id 
HAVING
	COUNT( E.department_id ) > 2;
#7.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
	E.employee_id,
	E.last_name,
	M.manager_id,
	M.last_name
FROM
	employees E,
	employees M 
WHERE
	E.employee_id = M.employee_id;