MySQL递归查询笔记

一、创建表结构和插入数据

二、查询所有子节点

三、查询所有父节点

四、查询指定节点的根节点

五、查询所有兄弟节点（同级节点）

六、获取祖先节点及其所有子节点

七、查询每个节点之间的层级关系

八、查询指定节点之间的层级关系

一、创建表结构和插入数据

CREATE TABLE `region` (  `id` VARCHAR(36) NOT NULL DEFAULT (UUID()) COMMENT '主键',  `parent_id` VARCHAR(36) COMMENT '父键',  `name` VARCHAR(255) NOT NULL COMMENT '地区名',  `latitude` DECIMAL(10, 6) COMMENT '经度',  `longitude` DECIMAL(10, 6) COMMENT '纬度',  PRIMARY KEY (`id`)  
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (NULL, '江苏省', 31.2304, 120.663);  SET @jiangsu_id = (SELECT `id` FROM `region` WHERE `name` = '江苏省');  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@jiangsu_id, '苏州市', 31.2988, 120.5853);  SET @suzhou_id = (SELECT `id` FROM `region` WHERE `name` = '苏州市');  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@suzhou_id, '张家港市', 31.8754, 120.5553),  (@suzhou_id, '吴中区', 31.2622, 120.6446),  (@suzhou_id, '相城区', 31.3697, 120.646),  (@suzhou_id, '吴江区', 31.1791, 120.6411);  SET @zhangjiagang_id = (SELECT `id` FROM `region` WHERE `name` = '张家港市');  
SET @wuzhong_id = (SELECT `id` FROM `region` WHERE `name` = '吴中区');  
SET @xiangcheng_id = (SELECT `id` FROM `region` WHERE `name` = '相城区');  
SET @wujiang_id = (SELECT `id` FROM `region` WHERE `name` = '吴江区');  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@zhangjiagang_id, '凤凰镇', 31.8754, 120.5553),  (@zhangjiagang_id, '塘桥镇', 31.8754, 120.5553);  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@wuzhong_id, '木渎镇', 31.2622, 120.6446);  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@xiangcheng_id, '黄埭镇', 31.3697, 120.646);  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@wujiang_id, '平望镇', 31.1791, 120.6411),   (@wujiang_id, '黎里镇', 31.1791, 120.6411);  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@jiangsu_id, '无锡市', 31.5704, 120.3055);  SET @wuxi_id = (SELECT `id` FROM `region` WHERE `name` = '无锡市');  INSERT INTO `region` (`parent_id`, `name`, `latitude`, `longitude`)   
VALUES (@wuxi_id, '锡山区', 31.5887, 120.3573),  (@wuxi_id, '惠山区', 31.6514, 120.3036),  (@wuxi_id, '滨湖区', 31.5502, 120.2598),  (@wuxi_id, '江阴市', 31.9086, 120.2855),  (@wuxi_id, '宜兴市', 31.3623, 119.8233);

二、查询所有子节点

从指定的父节点开始，递归查找所有子级地区：

WITH RECURSIVE region_cte AS (  SELECT id, name, parent_id  FROM region  WHERE name = '苏州市'  -- 根据指定父节点开始  UNION ALL  SELECT r.id, r.name, r.parent_id  FROM region r  JOIN region_cte c ON r.parent_id = c.id  -- 递归查找所有子地区  
)  
SELECT * FROM region_cte

查询结果：

三、查询所有父节点

从指定的子节点开始，递归查找所有父级地区：

WITH RECURSIVE region_cte AS (  SELECT id, name, parent_id  FROM region  WHERE name = '张家港市'  -- 从指定子节点开始  UNION ALL  SELECT r.id, r.name, r.parent_id  FROM region r  JOIN region_cte c ON r.id = c.parent_id  -- 递归查找父级区域  
)  
SELECT * FROM region_cte

查询结果：

四、查询指定节点的根节点

可以通过递归查找父节点，最终筛选出根节点（即没有父节点的）：

WITH RECURSIVE region_cte AS (  SELECT id, name, parent_id  FROM region  WHERE name = '张家港市'  -- 从指定节点开始  UNION ALL  SELECT r.id, r.name, r.parent_id  FROM region r  JOIN region_cte c ON r.id = c.parent_id  -- 递归查找父级区域  
)  
SELECT * FROM region_cte  
WHERE parent_id IS NULL  -- 筛选根节点

查询结果：

五、查询所有兄弟节点（同级节点）

查找与指定节点同级的所有区域：

SELECT id, name, parent_id  
FROM region  
WHERE parent_id = (SELECT parent_id FROM region WHERE name = '张家港市')  -- 获取同级父节点  
AND name != '张家港市'  -- 排除自身

查询结果：

六、获取祖先节点及其所有子节点

获取指定节点的祖先以及每个祖先的所有子节点：

WITH RECURSIVE region_ancestors AS (  SELECT id, name, parent_id  FROM region  WHERE name = '张家港市'  -- 从指定节点开始查找祖先  UNION ALL  SELECT r.id, r.name, r.parent_id  FROM region r  JOIN region_ancestors c ON r.id = c.parent_id  -- 递归查找所有父级区域  
),  
region_children AS (  SELECT id, name, parent_id  FROM region  UNION ALL  SELECT r.id, r.name, r.parent_id  FROM region r  JOIN region_children c ON r.parent_id = c.id  -- 递归查找所有子级区域  
)  
SELECT * FROM region_ancestors  
UNION  
SELECT * FROM region_children  
WHERE parent_id IN (SELECT id FROM region_ancestors)  -- 获取所有祖先的子节点

查询结果：

七、查询每个节点之间的层级关系

返回每个地区的详细信息，包括其层级和路径：

WITH RECURSIVE region_tree (id, name, parent_id, level, path) AS (  -- 选择根节点，即没有父节点的区域  SELECT  id,  name,  parent_id,  1 AS level,  CAST(name AS CHAR(200)) AS path  FROM region  WHERE parent_id IS NULL  UNION ALL  -- 递归查找子区域  SELECT  r.id,  r.name,  r.parent_id,  rt.level + 1 AS level,  CONCAT(rt.path, ' -> ', r.name) AS path  FROM region r  JOIN region_tree rt ON r.parent_id = rt.id  
)  
-- 查询结果  
SELECT  id, name, parent_id, level, path  
FROM region_tree  
ORDER BY id  -- 根据需要排序

查询结果：

八、查询指定节点之间的层级关系

假设获取苏州市（或其他特定节点）的所有子节点及其层级结构

WITH RECURSIVE region_tree (id, name, parent_id, level, path) AS (  -- 选择指定节点作为根节点  SELECT  id,  name,  parent_id,  1 AS level,  CAST(name AS CHAR(200)) AS path  FROM region  WHERE name = '苏州市'  -- 替换为你想要查询的节点名称  UNION ALL  -- 递归查找子区域  SELECT  r.id,  r.name,  r.parent_id,  rt.level + 1 AS level,  CONCAT(rt.path, ' -> ', r.name) AS path  FROM region r  JOIN region_tree rt ON r.parent_id = rt.id  
)  
-- 查询结果  
SELECT  id, name, parent_id, level, path  
FROM region_tree  
ORDER BY level, id  -- 根据层级和 ID 排序

查询结果：