[打卡]石浩洋 多表查询

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

SELECT employee_id,department_name
from employees e RIGHT join departments d
on e.department_id=d.department_id;