[打卡]彭迎弟 多表查询

SELECT e.employee_id,d.department_name
FROM employees e,departments d
WHERE e.department_id=d.department_id;

SELECT * FROM employees;
#外连接
SELECT e.employee_id,d.department_name
FROM employees e,departments d
WHERE e.department_id=d.department_id(+);
#内连接
SELECT e.employee_id,d.department_name
FROM employees e JOIN departments d
ON e.department_id=d.department_id;

SELECT e.employee_id,d.department_name,city
FROM employees e JOIN departments d
ON e.department_id=d.department_id
JOIN locations l
ON d.location_id=l.location_id;

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

SELECT e.employee_id,d.department_name
FROM employees e LEFT JOIN departments d
ON e.department_id=d.department_id;

SELECT e.employee_id,d.department_name
FROM employees e RIGHT OUTER JOIN departments d
ON e.department_id=d.department_id;