我如何获得 child 记录的 parent、grandparent 等及其本身以及与 SQL 中根的距离

Question

我有一个table如下图-

    ID | NAME        | PARENT

     1 | Global      | null 
     2 | USA         | 1
     3 | Canada      | 1
     4 | USA-1       | 2
     5 | USA-11      | 4

列 parent 指的是列 id，即 Global 是根。对于 USA-11，USA-1 是 parent，USA 是 grandparent，Global 是曾祖父 parent。 这是一个坚固的层次结构，可以上升到任何级别。我需要帮助编写一个查询，该查询将按以下方式扩展此层次结构 -

    ID | NAME        | PARENT    | Distance_from_parent

     1 | Global      | Global    | 0
     2 | USA         | USA       | 0
     2 | USA         | Global    | 1
     3 | Canada      | Canada    | 0
     3 | Canada      | Global    | 1
     4 | USA-1       | USA-1     | 0
     4 | USA-1       | USA       | 1
     4 | USA-1       | Global    | 2
     5 | USA-11      | USA-11    | 0
     5 | USA-11      | USA-1     | 1
     5 | USA-11      | USA       | 2
     5 | USA-11      | Global    | 3

因此，如果您注意到了，我在重复每个位置名称及其自身及其层次结构。 "distance_from_parent" 列是与 "Parent" 列中提到的 parent 的距离。

我尝试过使用 Connect By、Level 和 prior，但无法实现这种输出。

这个的 DDL 是 -

create table subsidiary (id number, name varchar2(50), parent number); 

insert into subsidiary (id, name, parent) values (1, 'Parent', null);
insert into subsidiary (id, name, parent) values (2, 'USA', 1);
insert into subsidiary (id, name, parent) values (3, 'Canada', 1);
insert into subsidiary (id, name, parent) values (4, 'USA-1', 2);
insert into subsidiary (id, name, parent) values (5, 'USA-11', 4);

Answer 1

您可以使用 CONNECT BY 获得您想要的结果：

SELECT s.id, s.name, CONNECT_BY_ROOT(s.name) AS ROOT_NAME, LEVEL-1 AS ROOT_DISTANCE
FROM subsidiary s
CONNECT BY s.parent = PRIOR(s.id)
ORDER BY s.id, LEVEL;

这是一个带有此解决方案的 SQLFiddle。 (Link)

Answer 2

使用分层查询 CONNECT_BY_ROOT:

SELECT CONNECT_BY_ROOT( ID ) AS id,
       CONNECT_BY_ROOT( name ) AS name,
       name AS parent,
       LEVEL - 1 AS distance_from_parent
FROM   subsidiary
CONNECT BY PRIOR parent = id
ORDER BY id, distance_from_parent;

所以对于你的测试数据：

CREATE TABLE subsidiary ( ID, NAME, PARENT ) AS
SELECT 1, 'Global', null FROM DUAL UNION ALL 
SELECT 2, 'USA',    1 FROM DUAL UNION ALL
SELECT 3, 'Canada', 1 FROM DUAL UNION ALL
SELECT 4, 'USA-1',  2 FROM DUAL UNION ALL
SELECT 5, 'USA-11', 4 FROM DUAL;

这输出：

ID | NAME   | PARENT | DISTANCE_FROM_PARENT
-: | :----- | :----- | -------------------:
 1 | Global | Global |                    0
 2 | USA    | USA    |                    0
 2 | USA    | Global |                    1
 3 | Canada | Canada |                    0
 3 | Canada | Global |                    1
 4 | USA-1  | USA-1  |                    0
 4 | USA-1  | USA    |                    1
 4 | USA-1  | Global |                    2
 5 | USA-11 | USA-11 |                    0
 5 | USA-11 | USA-1  |                    1
 5 | USA-11 | USA    |                    2
 5 | USA-11 | Global |                    3

db<>fiddle here

我如何获得 child 记录的 parent、grandparent 等及其本身以及与 SQL 中根的距离

How can i get a child record's parent, grandparent, and so on and itself along with the distance from root in SQL

sql

oracle

hierarchical-data

hierarchical-query