如何在沒有使用嵌套查詢的情況下找到沒有員工的部門？

Question

我有兩個表：

employee(e_id,e_name,d_id),department(d_id,d_name) 

我的查詢是：

select d.d_name from department d where d.d_id not in (
select distinct e.d_id from employee e); 

有任何替代辦法做到這一點？

Answer 1

試試這個。

select department.* from department 
    left join employee 
     on employee.d_id = department.d_id 
    where employee.d_id is null