Question

我有一个包含字段的表：

USER_ID
MANAGER_USER_ID
COST_CENTER

我需要查询所有这些数据，但是COST_CENTER应该来自经理，所以我做到了：

select USER_ID, COST_CENTER, MANAGER_USER_ID
from EMDB e
where COST_CENTER in (
    select COST_CENTER
    from EMDB e2
    where e2.USER_ID = e.MANAGER_USER_ID
    );

样本数据：

USER_ID    MANAGER_USER_ID    COST_CENTER
user1      user3              employeeCostCenter1
user2      user3              employeeCostCenter1
user3      manager3           employeeCostCenter2  <-- this is manager

Sample output:
USER_ID    MANAGER_USER_ID    COST_CENTER
user1      user3              employeeCostCenter2  
user1      user3              employeeCostCenter2  
user3      manager3           costCenterOfManager3

但是这不起作用（不返回任何内容）。有什么建议吗？

Answer 1

尝试一下：

select e.USER_ID,
       e.MANAGER_USER_ID
       e2.COST_CENTER             
    from EMDB e
      inner join EMDB e2 on e2.USER_ID = e.MANAGER_USER_ID

Answer 2

您可以使用此：

SELECT e.user_id, e.manager_user_id, e2.cost_center
FROM emdb e
INNER JOIN emdb e2
ON e2.user_id = e.manager_user_id;

Answer 3

以下是将子查询放入select子句的方法：

select 
  user_id, 
  manager_user_id,
  (select cost_center from emdb m where m.user_id = e.manager_user_id) as cost_center
from emdb e
order by user_id;

Oracle相关子查询

3 个答案: