《Mysql学习mysql递归查询实例解析》要点：
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导读：办法1,mysql递归查询.
/* Navicat MySQL Data Transfer Source Server : mysql_demo3 Source Server Version : 50521 Sourc...
MYSQL实例办法1,mysql递归查询.
/*
Navicat MySQL Data Transfer
Source Server : mysql_demo3
Source Server Version : 50521
Source Host : localhost:3306
Source Database : test
Target Server Type : MYSQL
Target Server Version : 50521
File Encoding : 65001
Date: 2012-09-02 21:16:03
*/
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for `treenodes`
-- ----------------------------
DROP TABLE IF EXISTS `treenodes`;
CREATE TABLE `treenodes` (
`id` int(11) NOT NULL,
`nodename` varchar(20) DEFAULT NULL,
`pid` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
-- ----------------------------
-- Records of treenodes
-- ----------------------------
INSERT INTO `treenodes` VALUES ('1', 'A', '0');
INSERT INTO `treenodes` VALUES ('2', 'B', '1');
INSERT INTO `treenodes` VALUES ('3', 'C', '1');
INSERT INTO `treenodes` VALUES ('4', 'D', '2');
INSERT INTO `treenodes` VALUES ('5', 'E', '2');
INSERT INTO `treenodes` VALUES ('6', 'F', '3');
INSERT INTO `treenodes` VALUES ('7', 'G', '6');
INSERT INTO `treenodes` VALUES ('8', 'H', '0');
INSERT INTO `treenodes` VALUES ('9', 'I', '8');
INSERT INTO `treenodes` VALUES ('10', 'J', '8');
INSERT INTO `treenodes` VALUES ('11', 'K', '8');
INSERT INTO `treenodes` VALUES ('12', 'L', '9');
INSERT INTO `treenodes` VALUES ('13', 'M', '9');
INSERT INTO `treenodes` VALUES ('14', 'N', '12');
INSERT INTO `treenodes` VALUES ('15', 'O', '12');
INSERT INTO `treenodes` VALUES ('16', 'P', '15');
INSERT INTO `treenodes` VALUES ('17', 'Q', '15');
MYSQL实例上边是sql脚本,在执行select * 之后显示的结果集如下：
mysql> select * from treenodes;
+----+----------+------+
| id | nodename | pid |
+----+----------+------+
| 1 | A | 0 |
| 2 | B | 1 |
| 3 | C | 1 |
| 4 | D | 2 |
| 5 | E | 2 |
| 6 | F | 3 |
| 7 | G | 6 |
| 8 | H | 0 |
| 9 | I | 8 |
| 10 | J | 8 |
| 11 | K | 8 |
| 12 | L | 9 |
| 13 | M | 9 |
| 14 | N | 12 |
| 15 | O | 12 |
| 16 | P | 15 |
| 17 | Q | 15 |
+----+----------+------+
17 rows in set (0.00 sec)
MYSQL实例树形图：
1:A
+-- 2:B
| +-- 4:D
| +-- 5:E
+-- 3:C
+-- 6:F
+-- 7:G
8:H
+-- 9:I
| +-- 12:L
| | +--14:N
| | +--15:O
| | +--16:P
| | +--17:Q
| +-- 13:M
+-- 10:J
+-- 11:K
MYSQL实例如果给你一个这样的table,让你查询根节点为1下的所有节点记录(注意也包括根节点)?
可能有不少人想到connect by 函数,但是我灰常遗憾的告诉你,咱这儿是mysql!
解决办法：利用函数来得到所有子节点号.
闲话少续,看我的解决办法
创建一个function getChildLst, 得到一个由所有子节点号组成的字符串.
mysql> delimiter //
mysql>
mysql> CREATE FUNCTION `getChildLst`(rootId INT)
RETURNS varchar(1000)
BEGIN
DECLARE sTemp VARCHAR(1000);
DECLARE sTempChd VARCHAR(1000);
SET sTemp = '$';
SET sTempChd =cast(rootId as CHAR);
WHILE sTempChd is not null DO
SET sTemp = concat(sTemp,',',sTempChd);
SELECT group_concat(id) INTO sTempChd FROM treeNodes where FIND_IN_SET(pid,sTempChd)>0;
END WHILE;
RETURN sTemp;
END
;
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> delimiter ;
MYSQL实例
使用我们直接利用find_in_set函数配合这个getChildlst来查找：
mysql> select getChildLst(1);
+-----------------+
| getChildLst(1) |
+-----------------+
| $,1,2,3,4,5,6,7 |
+-----------------+
1 row in set (0.00 sec)
mysql> select * from treeNodes
-> where FIND_IN_SET(id, getChildLst(1));
+----+----------+------+
| id | nodename | pid |
+----+----------+------+
| 1 | A | 0 |
| 2 | B | 1 |
| 3 | C | 1 |
| 4 | D | 2 |
| 5 | E | 2 |
| 6 | F | 3 |
| 7 | G | 6 |
+----+----------+------+
7 rows in set (0.01 sec)
mysql> select * from treeNodes
-> where FIND_IN_SET(id, getChildLst(3));
+----+----------+------+
| id | nodename | pid |
+----+----------+------+
| 3 | C | 1 |
| 6 | F | 3 |
| 7 | G | 6 |
+----+----------+------+
3 rows in set (0.01 sec)
MYSQL实例只要按我的做,百发百中百步穿杨,遇到问题万变不离其宗直接粘贴复制就是.
补充：
还可以做嵌套查询：
select id,pid from treeNodes where id in(
select id from treeNodes where FIND_IN_SET(id, getChildLst(3))
);
MYSQL实例子查询的结果集是：
+--------+
id
----
3
6
7
+-------+
然后,经过外层查询就是：
id pid
3 1
6 3
6 6
---------
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MySQL 递归查询当前节点子节点
mysql递归查询实现办法
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sql递归查询(with cte实现)
sql 递归查询的代码(图文)
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