[打卡]庞佳璇 多表查询

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

SELECT * FROM employees;

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

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

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

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

select employee_id,department_name
FROM employees e left outer join departments d
on e.department_id=d.department_id;

select employee_id,department_name
FROM employees e right outer join departments d
on e.department_id=d.department_id;