基于【 MySql 】三 || 复杂sql语句

目录

• 1、自关联表查询所有上级和下级信息
• 2、学习交流QQ群【883210148】

1、自关联表查询所有上级和下级信息

1.表结构如下所示（脚本数据请加QQ群免费获取）:

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

DROP TABLE IF EXISTS `hy_area`;
CREATE TABLE `hy_area`  (
  `id` int(0) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `pid` int(0) NULL DEFAULT NULL COMMENT '父id',
  `short_name` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '简称',
  `name` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '名称',
  `merger_name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '全称',
  `level` tinyint(0) NULL DEFAULT NULL COMMENT '层级 0 1 2 省市区县',
  `pinyin` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '拼音',
  `code` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '长途区号',
  `zip_code` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '邮编',
  `first` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '首字母',
  `lng` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '经度',
  `lat` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '纬度',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 3750 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;

SET FOREIGN_KEY_CHECKS = 1;

2.查询所有上级

-- 查询所有上级
SELECT
	T2.id,
	T2.pid,
	T2.short_name,
	T2.`name`,
	T2.merger_name,
	T2.`level`,
	T2.pinyin,
	T2.`code`,
	T2.zip_code,
	T2.`first`,
	T2.lng,
	T2.lat,
	T2.fid 
FROM
	(
	SELECT
		@r AS _id,
		( SELECT @r := pid FROM hy_area WHERE id = _id ) AS parent,
		@l := @l + 1 AS lvl 
	FROM
		( SELECT @r := 2682, @l := 3 ) vars,
		hy_area h 
	WHERE
		@r <> 0 
	) T1
	JOIN hy_area T2 ON T1._id = T2.id 
ORDER BY
	T2.id;

3.查询所有下级

-- 查询所有下级
SELECT
	T2.id,
	T2.pid,
	T2.short_name,
	T2.`name`,
	T2.merger_name,
	T2.`level`,
	T2.pinyin,
	T2.`code`,
	T2.zip_code,
	T2.`first`,
	T2.lng,
	T2.lat,
	T2.fid 
FROM
	(
	SELECT
		@ids AS _ids,
		( SELECT @ids := GROUP_CONCAT( id ) FROM hy_area WHERE FIND_IN_SET( pid, @ids ) ) AS cids,
		@l := @l + 1 AS lvl 
	FROM
		hy_area,
		( SELECT @ids := 2671, @l := 2 ) b 
	WHERE
		@ids IS NOT NULL 
	) id,
	hy_area T2
WHERE
	FIND_IN_SET( T2.id, id._ids ) 
ORDER BY
	lvl,
	id;

2、学习交流QQ群【883210148】