[打卡]崔志凯 多表查询

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


SELECT e.employee_id,d.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
from employees e 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 LEFT JOIN departments d
on e.department_id=d.department_id;