1

示例数据：

+----+-------+----------+
| org_id | Name  | ParentID |
+----+-------+----------+
|  1 | Org1  | 2        |
|  2 | Org2  | NULL     |
|  3 | Org3  | 5        |
|  5 | Org5  | 1        |
| 14 | Org14 | 1        |
+----+-------+----------+

如果我以 org_id 1 (Org1) 的用户身份登录。我想检索该用户的完整树。

我有以下递归查询：

WITH RECURSIVE cte (org_id, name, parent_id) AS (
     SELECT org_id, name, parent_id
     FROM organization
     WHERE org_id = 1
     UNION ALL
     SELECT t1.org_id, t1.name, t1.parent_id
     FROM organization t1
     INNER JOIN cte t2 ON t1.parent_id = t2.org_id
)
SELECT * FROM cte;

但是，这个查询只给了我当前 id 的孩子（在这个例子中是 Org1）。我怎样才能在结果集中也包括所有的父母，这样我就可以准确地重建整个树？

编辑：我正在使用 MariaDB 版本 10.4.10

编辑：我尝试了以下答案中的查询，我收到语法错误： 语法错误

4

1 回答 1

1

你有一个 CTE 可以得到孩子。为什么不使用另一个去相反的方向并得到父母：

MySQL：

(WITH RECURSIVE cte (id, name, parent_id) AS (
     SELECT id, name, parent_id
     FROM organization
     WHERE id = 1
     UNION  
     SELECT t1.id, t1.name, t1.parent_id
     FROM organization t1
       INNER JOIN cte t2 ON t1.parent_id = t2.id 
)
SELECT * FROM cte)
UNION
(WITH RECURSIVE cte (id, name, parent_id) AS (
     SELECT id, name, parent_id
     FROM organization
     WHERE id = 1
     UNION 
     SELECT t1.id, t1.name, t1.parent_id
     FROM organization t1
       INNER JOIN cte t2 ON t2.parent_id = t1.id 
)
SELECT * FROM cte)

还有一个同时适用于 MySQL 和 MariaDB 的版本：

MySQL/MariaDB：

WITH RECURSIVE cte (id, name, parent_id, dir) AS (
     SELECT id, name, parent_id, cast(null as char(10)) as dir
     FROM organization
     WHERE id = 1
     UNION  
     SELECT t1.id, t1.name, t1.parent_id, ifnull(t2.dir, 'down')
     FROM organization t1
       INNER JOIN cte t2 ON t1.parent_id = t2.id and ifnull(t2.dir, 'down')='down'
     UNION
     SELECT t1.id, t1.name, t1.parent_id, ifnull(t2.dir, 'up')
     FROM organization t1
       INNER JOIN cte t2 ON t2.parent_id = t1.id and ifnull(t2.dir, 'up')='up'
)
SELECT id, name, parent_id FROM cte;

参见db-fiddle和dbfiddle

于 2020-02-01T17:08:24.610 回答