如何在單個SQL查詢中顯示：哪些部門沒有任何員工，哪些員工沒有部門（Oracle SQL）？

Question

我一直在試圖弄清楚這一段時間，仍然沒有運氣。我是否將以下內容與'is null'結合？

select distinct 
     e.employee_id, e.last_name, e.department_id, 
     d.department_id, d.location_id 
from employees e 
    join departments d on (e.department_id = d.department_id) 

Answer 1

例如基於Joe的評論

select distinct 
     e.employee_id, e.last_name, e.department_id, 
     d.department_id, d.location_id 
from employees e 
    full outer join departments d on (e.department_id = d.department_id) 
where e.department_id is null or d.department_id is null 

或者這種方式與union

select distinct 
     e.employee_id, e.last_name, e.department_id, 
     d.department_id, d.location_id 
from employees e 
    left outer join departments d on (e.department_id = d.department_id) 
where d.department_id is null 
union 
select distinct 
     e.employee_id, e.last_name, e.department_id, 
     d.department_id, d.location_id 
from employees e 
    right outer join departments d on (e.department_id = d.department_id) 
where e.department_id is null