SQL Query获取所有管理器

Question

我有一个SQL表worker，其字段为：

1. id
2. Name
3. Manager id

我正在尝试编写查询以获取以下字段列表（'id'，'name'，'manager id'，'manager name'）

请注意，经理ID也属于工作人员，即经理也是工人。此外，经理还有一个经理，他再次属于同一个表 - 层次结构可以升级到n个经理（未知）。

到目前为止，这是我的查询

SELECT tab1.user_name, tab1.user_id, tab1.manager_id, tab2.name AS manager_name, 1 AS LEVEL FROM (SELECT tab1.name AS user_name, tab1.id AS user_id, manager_id FROM DB.user tab1 WHERE id = 1 AND active = 1) tab1 LEFT JOIN DB.user tab2 ON tab1.manager_id = tab2.id UNION SELECT tab1.user_name, tab1.user_id, tab1.manager_id, tab2.name AS manager_name, 2 AS LEVEL FROM (SELECT tab1.name AS user_name, tab1.id AS user_id, manager_id FROM DB.user tab1 WHERE manager_id = 1 AND active = 1) tab1 LEFT JOIN DB.user tab2 ON tab1.manager_id = tab2.id UNION SELECT tab1.user_name, tab1.user_id, tab1.manager_id, tab2.name AS manager_name, 3 AS LEVEL FROM (SELECT tab1.name AS user_name, tab1.id AS user_id, manager_id FROM DB.user tab1 WHERE manager_id IN (SELECT tab1.id FROM DB.user tab1 WHERE manager_id = 1 AND active = 1) AND active = 1 ) tab1 LEFT JOIN DB.user tab2 ON tab1.manager_id = tab2.id

但是这让我得到了结果，直到第3级的heirarchy，而我需要它自我扩展并且无论嵌套存在什么级别都可以获取结果。

有人可以帮忙吗。

Answer 1

select w1.id, w1.name, w2.id as manager_id, w2.name as manager_name
from worker as w1 inner join worker w2 on w1.manager_id = w2.id