[打卡]苏首陇 多表查询

select employee_id,department_name
from employees e,departments d
where e.employee_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,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 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;