sql - Postgresql 递归返回意外结果

Question

我正在尝试检索特定经理的整个员工层次结构。

表格如下:

id :: int
manager :: foreign key(users)

数据:

| id  | manager | 
-----------------
| 103 | 138     |
| 125 | 138     |
| 114 | 103     |
| 122 | 103     |
| 138 | NULL    |
| 144 | 222     |
| 222 | NULL    |

当我执行以下递归时:

WITH RECURSIVE managed AS (
        SELECT manager AS manager_id, id AS employee_id
        FROM users
        WHERE manager = 138
    UNION 
        SELECT u2.manager AS manager_id, u2.id as employee_id
        FROM users u2 
        INNER JOIN managed m ON m.employee_id = u2.id
    )


select *
from managed;

我收到了错误的结果:

虽然预期是:(完全如以下链接所示...)

| employee_id  | manager_id | 
-----------------------------
| 103          | 138        |
| 125          | 138        |
| 114          | 103        |
| 122          | 103        |

我试过很多例子包括::this one ，这与我的问题类似，但没有一个有效......

当我尝试使用 UNION ALL 执行查询时，执行永远不会结束(几分钟后我不得不取消执行)

提前致谢:)

Answer 1

您有一个小错误 - 您需要加入 m.employee_id = u2.manager 而不是 m.employee_id = u2.id:

WITH RECURSIVE managed AS (
        SELECT manager AS manager_id, id AS employee_id
        FROM users
        WHERE manager = 138
    UNION 
        SELECT u2.manager AS manager_id, u2.id as employee_id
        FROM users u2 
        INNER JOIN managed m ON m.employee_id = u2.manager
    )


select *
from managed;

结果是:

 manager_id | employee_id 
------------+-------------
        138 |         103
        138 |         125
        103 |         114
        103 |         122
(4 rows)