sql - Oracle 11g 中的 USING 子句

Question

 select e.employee_id,e.last_name,e.department_id,
         d.department_name,l.city,l.location_id
 from employees e 
 join departments d
      on e.department_id=d.department_id
 join locations l
      on l.location_id=d.location_id
 and e.manager_id=149;

我们可以用“USING”子句替换“ON”子句吗？-使用oracle 11g中的Employees、Departments、Locations表。尝试一下。

Answer 1

不，您不能仅将 ON 替换为 USING。但是您可以重写查询以在连接中包含 USING 子句。请参阅下面的正确语法:

select e.employee_id,
       e.last_name,
       department_id, --Note there is no table prefix
       d.department_name,
       l.city,
       location_id --Note there is no table prefix
  from employees e
  join departments d
 using (department_id)
  join locations l
 using (location_id)
 where e.manager_id = 149;