from:https://yq.aliyun.com/articles/48885
最近遇到了一个问题,在mysql中如何完成节点下的所有节点或节点上的所有父节点的查询?
在Oracle中我们知道有一个Hierarchical Queries可以通过CONNECT BY来查询,但是,在MySQL中还没有对应的函数!!!
下面给出一个function
来完成的方法
下面是sql脚本,想要运行的直接赋值粘贴进数据库即可。
创建表treenodes
(可以根据需要进行更改)
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| -- ---------------------------- -- 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;
|
插入几条数据
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| -- ---------------------------- -- 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');
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把下面的语句直接粘贴进命令行执行即可(注意修改传入的参数,默认rootId,表明默认treenodes)
根据传入id查询所有父节点的id
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| delimiter // CREATE FUNCTION `getParLst`(rootId INT) RETURNS varchar(1000)
BEGIN DECLARE sTemp VARCHAR(1000); DECLARE sTempPar VARCHAR(1000); SET sTemp = ''; SET sTempPar =rootId; #循环递归 WHILE sTempPar is not null DO #判断是否是第一个,不加的话第一个会为空 IF sTemp != '' THEN SET sTemp = concat(sTemp,',',sTempPar); ELSE SET sTemp = sTempPar; END IF;
SET sTemp = concat(sTemp,',',sTempPar); SELECT group_concat(pid) INTO sTempPar FROM treenodes where pid<>id and FIND_IN_SET(id,sTempPar)>0; END WHILE; RETURN sTemp; END //
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执行命令
select getParList(15);
结果:
id | nodename | pid |
---|
8 | H | 0 |
9 | I | 8 |
12 | L | 9 |
15 | O | 12 |
根据传入id查询所有子节点的id
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| delimiter // CREATE FUNCTION `getParLst`(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 //
|
执行命令
select getChildList(7);
结果: