Mysql中的递归层次查询（父子查询,无限极查询）

前言：最近面试的时候遇到公司要求只能用SQL来查询无限极的数据，不能用PHP程序做递归查询，现在分享方法。

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。

  

   

    

     

    
    

     

      -- ---------------------------- 
     
    
   

    

     

    
    

     

      -- 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');
     
    
  
 

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

方法1:

级数不知道，可以用类似下面这个语句查询, @r := 6为查询条件

  

   

    

     

    
    

     

      SELECT T2.id, T2.nodename, T2.pid
     
    
   

    

     

    
    

     

      FROM ( 
     
    
   

    

     

    
    

     
    SELECT 
     
    
   

    

     

    
    

     

              @r AS _id, 
     
    
   

    

     

    
    

     

              (SELECT @r := pid FROM treenodes WHERE id = _id) AS pid, 
     
    
   

    

     

    
    

     

              @l := @l + 1 AS l
     
    
   

    

     

    
    

     
    FROM 
     
    
   

    

     

    
    

     

              (SELECT @r := 6, @l := 0) vars, 
     
    
   

    

     

    
    

     

              treenodes h 
     
    
   

    

     

    
    

     
    WHERE @r != 0) T1 
     
    
   

    

     

    
    

     

      JOIN treenodes T2 
     
    
   

    

     

    
    

     

      ON T1._id = T2.id 
     
    
   

    

     

    
    

     

      ORDER BY T1.l;
     
    
  
 

结果:

方法2:

  

   

    

     

    
    

     

      delimiter // 
     
    
   

    

     

    
    

     

      CREATE FUNCTION `getParList`(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
     
    
   

    

     

    
    

     

      //
     
    
  
 

执行命令

select * from treenodes where FIND_IN_SET(id,getParList(15));
 

结果： 

根据传入id查询所有子节点的id

  

   

    

     

    
    

     

      delimiter // 
     
    
   

    

     

    
    

     

      CREATE FUNCTION `getChildList`(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 * from treenodes where FIND_IN_SET(id,getChildList(7));

 

结果：

文章来源: lansonli.blog.csdn.net，作者：Lansonli，版权归原作者所有，如需转载，请联系作者。

原文链接：lansonli.blog.csdn.net/article/details/103105002