PostgreSQL数据库使用sql语句递归分别实现查询所有的子节点、所有的父节点：with查询

目录

一、环境

二、准备数据

三、根据父节点ID获取所有子节点

四、根据子节点获取所有的父节点

---

一、环境

数据库：Postgresql

二、准备数据

/*
Navicat PGsql Data Transfer

Source Server         : localhost_postgresql
Source Server Version : 90617
Source Host           : localhost:5432
Source Database       : odc_test
Source Schema         : public

Target Server Type    : PGsql
Target Server Version : 90617
File Encoding         : 65001

Date: 2021-04-30 22:22:15
*/


-- ----------------------------
-- Table structure for sys_area
-- ----------------------------
DROP TABLE IF EXISTS "public"."sys_area";
CREATE TABLE "public"."sys_area" (
"id" int8 NOT NULL,
"name" varchar(100) COLLATE "default" NOT NULL,
"parent_id" int8
)
WITH (OIDS=FALSE)

;

-- ----------------------------
-- Records of sys_area
-- ----------------------------
INSERT INTO "public"."sys_area" VALUES ('1', '重庆市', null);
INSERT INTO "public"."sys_area" VALUES ('2', '渝中区', '1');
INSERT INTO "public"."sys_area" VALUES ('3', '九龙坡区', '1');
INSERT INTO "public"."sys_area" VALUES ('4', '开州区', '1');
INSERT INTO "public"."sys_area" VALUES ('5', '渝北区', '1');
INSERT INTO "public"."sys_area" VALUES ('6', '两江新区', '1');
INSERT INTO "public"."sys_area" VALUES ('7', '石桥铺街道', '3');
INSERT INTO "public"."sys_area" VALUES ('8', '二郎街道', '3');
INSERT INTO "public"."sys_area" VALUES ('9', '大进镇', '4');

-- ----------------------------
-- Alter Sequences Owned By 
-- ----------------------------

-- ----------------------------
-- Primary Key structure for table sys_area
-- ----------------------------
ALTER TABLE "public"."sys_area" ADD PRIMARY KEY ("id");

三、根据父节点ID获取所有子节点

WITH RECURSIVE cte AS (
	SELECT
		n. ID,
		n. NAME,
		n.parent_id AS pid
	FROM
		sys_area AS n
	WHERE
		n. ID = 1
	UNION ALL
		SELECT
			r. ID,
			r. NAME,
			cte. ID AS pid
		FROM
			cte
		JOIN sys_area AS r ON r.parent_id = cte. ID
) SELECT
	*
FROM
	cte

结果信息：

四、根据子节点获取所有的父节点

WITH RECURSIVE cte AS (
	SELECT
		n. ID,
		n. NAME,
		n.parent_id AS pid
	FROM
		sys_area AS n
	WHERE
		n. NAME LIKE '%二郎%'
	UNION ALL
		SELECT
			r. ID,
			r. NAME,
			r.parent_id AS pid
		FROM
			cte
		JOIN sys_area AS r ON cte.pid = r. ID
) SELECT
	*
FROM
	cte

结果信息：