對於資料庫中的樹形結構資料，如部門表，有時候，我們需要知道某部門的所有下屬部分或者某部分的所有上級部門，這時候就需要用到mysql的遞迴查詢。

1、建立表

DROP TABLE IF EXISTS `t_areainfo`;
CREATE TABLE `t_areainfo` (
 `id` int(11) NOT '0' AUTO_INCREMENT,
 `level` int(11) DEFAULT '0',
 `name` varchar(255) DEFAULT '0',
 `parentId` int(11) DEFAULT '0',
 `status` int(11) DEFAULT '0',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=65 DEFAULT CHARSET=utf8;

2、初始資料

INSERT INTO `t_areainfo` VALUES ('1', '0', '中國', '0', '0');
INSERT INTO `t_areainfo` VALUES ('2', '0', '華北區', '1', '0');
INSERT INTO `t_areainfo` VALUES ('3', '0', '華南區', '1', '0');
INSERT INTO `t_areainfo` VALUES ('4', '0', '北京', '2', '0');
INSERT INTO `t_areainfo` VALUES ('5', '0', '海淀區', '4', '0');
INSERT INTO `t_areainfo` VALUES ('6', '0', '豐臺區', '4', '0');
INSERT INTO `t_areainfo` VALUES ('7', '0', '朝陽區', '4', '0');
INSERT INTO `t_areainfo` VALUES ('8', '0', '北京XX區1', '4', '0');
INSERT INTO `t_areainfo` VALUES ('9', '0', '北京XX區2', '4', '0');
INSERT INTO `t_areainfo` VALUES ('10', '0', '北京XX區3', '4', '0');
INSERT INTO `t_areainfo` VALUES ('11', '0', '北京XX區4', '4', '0');
INSERT INTO `t_areainfo` VALUES ('12', '0', '北京XX區5', '4', '0');
INSERT INTO `t_areainfo` VALUES ('13', '0', '北京XX區6', '4', '0');
INSERT INTO `t_areainfo` VALUES ('14', '0', '北京XX區7', '4', '0');
INSERT INTO `t_areainfo` VALUES ('15', '0', '北京XX區8', '4', '0');
INSERT INTO `t_areainfo` VALUES ('16', '0', '北京XX區9', '4', '0');
INSERT INTO `t_areainfo` VALUES ('17', '0', '北京XX區10', '4', '0');
INSERT INTO `t_areainfo` VALUES ('18', '0', '北京XX區11', '4', '0');
INSERT INTO `t_areainfo` VALUES ('19', '0', '北京XX區12', '4', '0');
INSERT INTO `t_areainfo` VALUES ('20', '0', '北京XX區13', '4', '0');
INSERT INTO `t_areainfo` VALUES ('21', '0', '北京XX區14', '4', '0');
INSERT INTO `t_areainfo` VALUES ('22', '0', '北京XX區15', '4', '0');
INSERT INTO `t_areainfo` VALUES ('23', '0', '北京XX區16', '4', '0');
INSERT INTO `t_areainfo` VALUES ('24', '0', '北京XX區17', '4', '0');
INSERT INTO `t_areainfo` VALUES ('25', '0', '北京XX區18', '4', '0');
INSERT INTO `t_areainfo` VALUES ('26', '0', '北京XX區19', '4', '0');
INSERT INTO `t_areainfo` VALUES ('27', '0', '北京XX區1', '4', '0');
INSERT INTO `t_areainfo` VALUES ('28', '0', '北京XX區2', '4', '0');
INSERT INTO `t_areainfo` VALUES ('29', '0', '北京XX區3', '4', '0');
INSERT INTO `t_areainfo` VALUES ('30', '0', '北京XX區4', '4', '0');
INSERT INTO `t_areainfo` VALUES ('31', '0', '北京XX區5', '4', '0');
INSERT INTO `t_areainfo` VALUES ('32', '0', '北京XX區6', '4', '0');
INSERT INTO `t_areainfo` VALUES ('33', '0', '北京XX區7', '4', '0');
INSERT INTO `t_areainfo` VALUES ('34', '0', '北京XX區8', '4', '0');
INSERT INTO `t_areainfo` VALUES ('35', '0', '北京XX區9', '4', '0');
INSERT INTO `t_areainfo` VALUES ('36', '0', '北京XX區10', '4', '0');
INSERT INTO `t_areainfo` VALUES ('37', '0', '北京XX區11', '4', '0');
INSERT INTO `t_areainfo` VALUES ('38', '0', '北京XX區12', '4', '0');
INSERT INTO `t_areainfo` VALUES ('39', '0', '北京XX區13', '4', '0');
INSERT INTO `t_areainfo` VALUES ('40', '0', '北京XX區14', '4', '0');
INSERT INTO `t_areainfo` VALUES ('41', '0', '北京XX區15', '4', '0');
INSERT INTO `t_areainfo` VALUES ('42', '0', '北京XX區16', '4', '0');
INSERT INTO `t_areainfo` VALUES ('43', '0', '北京XX區17', '4', '0');
INSERT INTO `t_areainfo` VALUES ('44', '0', '北京XX區18', '4', '0');
INSERT INTO `t_areainfo` VALUES ('45', '0', '北京XX區19', '4', '0');
INSERT INTO `t_areainfo` VALUES ('46', '0', 'xx省1', '1', '0');
INSERT INTO `t_areainfo` VALUES ('47', '0', 'xx省2', '1', '0');
INSERT INTO `t_areainfo` VALUES ('48', '0', 'xx省3', '1', '0');
INSERT INTO `t_areainfo` VALUES ('49', '0', 'xx省4', '1', '0');
INSERT INTO `t_areainfo` VALUES ('50', '0', 'xx省5', '1', '0');
INSERT INTO `t_areainfo` VALUES ('51', '0', 'xx省6', '1', '0');
INSERT INTO `t_areainfo` VALUES ('52', '0', 'xx省7', '1', '0');
INSERT INTO `t_areainfo` VALUES ('53', '0', 'xx省8', '1', '0');
INSERT INTO `t_areainfo` VALUES ('54', '0', 'xx省9', '1', '0');
INSERT INTO `t_areainfo` VALUES ('55', '0', 'xx省10', '1', '0');
INSERT INTO `t_areainfo` VALUES ('56', '0', 'xx省11', '1', '0');
INSERT INTO `t_areainfo` VALUES ('57', '0', 'xx省12', '1', '0');
INSERT INTO `t_areainfo` VALUES ('58', '0', 'xx省13', '1', '0');
INSERT INTO `t_areainfo` VALUES ('59', '0', 'xx省14', '1', '0');
INSERT INTO `t_areainfo` VALUES ('60', '0', 'xx省15', '1', '0');
INSERT INTO `t_areainfo` VALUES ('61', '0', 'xx省16', '1', '0');
INSERT INTO `t_areainfo` VALUES ('62', '0', 'xx省17', '1', '0');
INSERT INTO `t_areainfo` VALUES ('63', '0', 'xx省18', '1', '0');
INSERT INTO `t_areainfo` VALUES ('64', '0', 'xx省19', '1', '0');

3、向下遞迴

利用find_in_set()函式和group_concat()函式實現遞迴查詢：

DROP FUNCTION IF EXISTS queryChildrenAreaInfo;DELIMITER ;;
CREATE FUNCTION queryChildrenAreaInfo(areaId INT)
RETURNS VARCHAR(4000)
BEGIN
DECLARE sTemp VARCHAR(4000);
DECLARE sTempChd VARCHAR(4000);

SET sTemp='$';
SET sTempChd = CAST(areaId AS CHAR);

WHILE sTempChd IS NOT NULL DO
SET sTemp= CONCAT(sTemp,',',sTempChd);
SELECT GROUP_CONCAT(id) INTO sTempChd FROM t_areainfo WHERE FIND_IN_SET(parentId,sTempChd)>0;
END WHILE;
RETURN sTemp;
END;;DELIMITER ;

4、呼叫方式

查詢id為"4"下面的所有節點：

SELECT * FROM t_areainfo WHERE FIND_IN_SET(id,queryChildrenAreaInfo(4));

5、向上遞迴

DROP FUNCTION IF EXISTS queryChildrenAreaInfo1;DELIMITER;;
CREATE FUNCTION queryChildrenAreaInfo1(areaId INT)
RETURNS VARCHAR(4000)
BEGIN
DECLARE sTemp VARCHAR(4000);
DECLARE sTempChd VARCHAR(4000);

SET sTemp='$';
SET sTempChd = CAST(areaId AS CHAR);
SET sTemp = CONCAT(sTemp,',',sTempChd);

SELECT parentId INTO sTempChd FROM t_areainfo WHERE id = sTempChd;
WHILE sTempChd <> 0 DO
SET sTemp = CONCAT(sTemp,',',sTempChd);
SELECT parentId INTO sTempChd FROM t_areainfo WHERE id = sTempChd;
END WHILE;
RETURN sTemp;
END;;DELIMITER ;

6、呼叫方式

查詢id為"7"的節點的所有上級節點：

SELECT * from t_areainfo where FIND_IN_SET(id,queryChildrenAreaInfo1(7));