oracle的递归写法：地区层级

前言

mysql的递归看我另一篇博文：https://www.cnblogs.com/daen/p/17252369.html

表结构

数据

查询子节点

示例

SELECT
	cx1.*
FROM
	PHCP_CITY cx1
WHERE
	cx1.IS_ENABLE = 1 START WITH cx1.CITY_CODE = '370100' CONNECT BY PRIOR cx1.CITY_CODE = cx1.PARENT_ID

结果

不含自己的写法

加个不等于即可

查询父节点

示例

SELECT
	cx1.*
FROM
	PHCP_CITY cx1
WHERE
	cx1.IS_ENABLE = 1 START WITH cx1.CITY_CODE = '370112' CONNECT BY cx1.CITY_CODE = PRIOR cx1.PARENT_ID

结果

不含自己的写法

加个不等于即可

查询子节点和父节点的区别

其实就是将 PRIOR放到了PARENT_ID 前面而已

多行合并一行

就是我输入一个地区CODE，然后获取到他的所有的父级的名称，拼接成一个字符串

写法一

WITH temp AS (
	SELECT
		cx1.*
	FROM
		PHCP_CITY cx1
	WHERE
		cx1.IS_ENABLE = 1 START WITH cx1.CITY_CODE = '370112' CONNECT BY cx1.CITY_CODE = PRIOR cx1.PARENT_ID
	) SELECT
	listagg ( CITY_NAME, '#' ) within GROUP ( ORDER BY IS_ENABLE, CITY_LEVEL ) AS brands
FROM
	temp
GROUP BY
	IS_ENABLE;

写法二

SELECT
	listagg ( CITY_NAME, '#' ) within GROUP ( ORDER BY IS_ENABLE, CITY_LEVEL ) AS brands
FROM
	(
	SELECT
		cx1.CITY_CODE,
		CITY_NAME,
		IS_ENABLE,
		CITY_LEVEL
	FROM
		PHCP_CITY cx1
	WHERE
		cx1.IS_ENABLE = 1 START WITH cx1.CITY_CODE = '370112' CONNECT BY cx1.CITY_CODE = PRIOR cx1.PARENT_ID
	ORDER BY
		CITY_LEVEL
	)
GROUP BY
	IS_ENABLE;

结果