--1.顯示所有員工的姓名，部門號和部門名稱
select last_name,department_id,department_name
from employees e,departments d
where e.department_id=d.department_id(+)
select last_name,e.department_id,department_name
from employees e left outer join departments d
on e.department_id =d.department_id
--2.查詢90號部門員工的job_id和90號部門的location_id
select distinct job_id,location_id
from employees e left outer join department d
on e.department_id=d.department_id
where d.department_id=90
--3.選擇所有有獎金的員工的資訊
select last_name,department_name,d.location_id,city
from employees e join departments d
on e.department_id=d.department_id
join lacation l
on d.location_id=l.location_id
where e.commission_pct is not null;
--4,選擇city在toronto工作的員工的
select last_name,job_id,department_id,department_id
from employees e ,departments d,locations l
where e.department_id=d.department_id and l.city='toronto'
and d.location_id=l.lacation_id;
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