Oracle SQL 从下到上元素分层查询

Question

在我的 table 中，我存储了每个条目的后继者。

+----+-----------+--+
| ID | SUCCESSOR |  |
+----+-----------+--+
|  1 |         2 |  |
|  2 |         3 |  |
|  3 |           |  |
+----+-----------+--+

我需要从 ID 3 到 ID 1.

我试图通过以下查询来实现这一点，但这不起作用。 :-(

SELECT NVL (id, 3)
FROM my_table
WHERE LEVEL = 1
CONNECT BY id = PRIOR successor
START WITH id = 3;

有人可以给我一些如何让它工作的建议吗？

Answer 1

以下版本也应该提供正确答案：

with my_table as 
(select 1 id, 2 successor from dual union
select 2 id, 3 successor from dual union
select 3 id, null successor from dual )
SELECT id FROM my_table
WHERE level = 3
CONNECT BY successor = PRIOR id 
START WITH successor is null
;

Oracle SQL 从下到上元素分层查询

Oracle SQL hierarchical query from bottom to top element

sql

oracle

hierarchical