数据库中如何多次join同一个表

select o1.emp_name as 员工姓名1 , o2.emp_name as 员工姓名2 from tableTest
join employee o1
on tabletest.[Emp_ID1] = o1.[emp_id] 
join employee o2
on tabletest.[Emp_ID2] = o2.[emp_id]

两次分别用了不同的别名o1，o2