[MySQL] 实现树形的遍历（关于多级菜单栏以及多级上下部门的查询问题） - huanshare - 博客园
**前言：
**
关于多级别菜单栏或者权限系统中部门上下级的树形遍历，oracle中有connect by来实现，MySQL没有这样的便捷途径，所以MySQL遍历数据表是我们经常会遇到的头痛问题，下面通过存储过程来实现。
**如果在执行SQL语句的时候报错，删除END后的￥符号即可
**
1，建立测试表和数据：
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DROP TABLE IF EXISTS csdn.channel; CREATE TABLE csdn.channel (
id INT(11) NOT NULL AUTO_INCREMENT,
cname VARCHAR(200) DEFAULT NULL,
parent_id INT(11) DEFAULT NULL, PRIMARY KEY (id)
) ENGINE=INNODB DEFAULT CHARSET=utf8; INSERT INTO channel(id,cname,parent_id) VALUES (13,'首页',-1),
(14,'TV580',-1),
(15,'生活580',-1),
(16,'左上幻灯片',13),
(17,'帮忙',14),
(18,'栏目简介',17); DROP TABLE IF EXISTS channel;
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2，利用临时表和递归过程实现树的遍历（mysql的UDF不能递归调用）：
2.1，从某节点向下遍历子节点，递归生成临时表数据
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-- pro_cre_childlist
DELIMITER $$ DROP PROCEDURE IF EXISTS csdn.pro\_cre\_childlist$$ CREATE PROCEDURE csdn.pro_cre_childlist(IN rootId INT,IN nDepth INT) BEGIN
DECLARE done INT DEFAULT 0; DECLARE b INT; DECLARE cur1 CURSOR FOR SELECT id FROM channel WHERE parent_id=rootId; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max\_sp\_recursion_depth=12; INSERT INTO tmpLst VALUES (NULL,rootId,nDepth); OPEN cur1; FETCH cur1 INTO b; WHILE done=0 DO
CALL pro\_cre\_childlist(b,nDepth+1); FETCH cur1 INTO b; END WHILE; CLOSE cur1; END$$
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2.2，从某节点向上追溯根节点，递归生成临时表数据
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-- pro_cre_parentlist
DELIMITER $$ DROP PROCEDURE IF EXISTS csdn.pro\_cre\_parentlist$$ CREATE PROCEDURE csdn.pro_cre_parentlist(IN rootId INT,IN nDepth INT) BEGIN
DECLARE done INT DEFAULT 0; DECLARE b INT; DECLARE cur1 CURSOR FOR SELECT parent_id FROM channel WHERE id=rootId; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max\_sp\_recursion_depth=12; INSERT INTO tmpLst VALUES (NULL,rootId,nDepth); OPEN cur1; FETCH cur1 INTO b; WHILE done=0 DO
CALL pro\_cre\_parentlist(b,nDepth+1); FETCH cur1 INTO b; END WHILE; CLOSE cur1; END$$
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2.3，实现类似Oracle SYS_CONNECT_BY_PATH的功能，递归过程输出某节点id路径
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-- pro_cre_pathlist
DELIMITER $$ USE csdn$$ DROP PROCEDURE IF EXISTS pro_cre_pathlist$$ CREATE PROCEDURE pro_cre_pathlist(IN nid INT,IN delimit VARCHAR(10),INOUT pathstr VARCHAR(1000)) BEGIN
DECLARE done INT DEFAULT 0; DECLARE parentid INT DEFAULT 0; DECLARE cur1 CURSOR FOR
SELECT t.parent_id,CONCAT(CAST(t.parent_id AS CHAR),delimit,pathstr) FROM channel AS t WHERE t.id = nid; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max\_sp\_recursion_depth=12; OPEN cur1; FETCH cur1 INTO parentid,pathstr; WHILE done=0 DO
CALL pro\_cre\_pathlist(parentid,delimit,pathstr); FETCH cur1 INTO parentid,pathstr; END WHILE; CLOSE cur1; END$$
DELIMITER ;
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2.4，递归过程输出某节点name路径
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-- pro_cre_pnlist
DELIMITER $$ USE csdn$$ DROP PROCEDURE IF EXISTS pro_cre_pnlist$$ CREATE PROCEDURE pro_cre_pnlist(IN nid INT,IN delimit VARCHAR(10),INOUT pathstr VARCHAR(1000)) BEGIN
DECLARE done INT DEFAULT 0; DECLARE parentid INT DEFAULT 0; DECLARE cur1 CURSOR FOR
SELECT t.parent_id,CONCAT(t.cname,delimit,pathstr) FROM channel AS t WHERE t.id = nid; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max\_sp\_recursion_depth=12; OPEN cur1; FETCH cur1 INTO parentid,pathstr; WHILE done=0 DO
CALL pro\_cre\_pnlist(parentid,delimit,pathstr); FETCH cur1 INTO parentid,pathstr; END WHILE; CLOSE cur1; END$$
DELIMITER ;
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2.5，调用函数输出id路径
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-- fn_tree_path
DELIMITER $$ DROP FUNCTION IF EXISTS csdn.fn\_tree\_path$$ CREATE FUNCTION csdn.fn_tree_path(nid INT,delimit VARCHAR(10)) RETURNS VARCHAR(2000) CHARSET utf8 BEGIN
DECLARE pathid VARCHAR(1000); SET @pathid=CAST(nid AS CHAR);
CALL pro_cre_pathlist(nid,delimit,@pathid); RETURN @pathid; END$$
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2.6，调用函数输出name路径
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-- fn_tree_pathname -- 调用函数输出name路径
DELIMITER $$ DROP FUNCTION IF EXISTS csdn.fn\_tree\_pathname$$ CREATE FUNCTION csdn.fn_tree_pathname(nid INT,delimit VARCHAR(10)) RETURNS VARCHAR(2000) CHARSET utf8 BEGIN
DECLARE pathid VARCHAR(1000); SET @pathid='';
CALL pro_cre_pnlist(nid,delimit,@pathid); RETURN @pathid; END$$
DELIMITER ;
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2.7，调用过程输出子节点
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-- pro_show_childLst
DELIMITER $$ -- 调用过程输出子节点
DROP PROCEDURE IF EXISTS pro_show_childLst$$ CREATE PROCEDURE pro_show_childLst(IN rootId INT) BEGIN
DROP TEMPORARY TABLE IF EXISTS tmpLst; CREATE TEMPORARY TABLE IF NOT EXISTS tmpLst
(sno INT PRIMARY KEY AUTO_INCREMENT,id INT,depth INT);
CALL pro\_cre\_childlist(rootId,0); SELECT channel.id,CONCAT(SPACE(tmpLst.depth*2),'--',channel.cname) NAME,channel.parent\_id,tmpLst.depth,fn\_tree_path(channel.id,'/') path,fn\_tree\_pathname(channel.id,'/') pathname FROM tmpLst,channel WHERE tmpLst.id=channel.id ORDER BY tmpLst.sno; END$$
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2.8，调用过程输出父节点
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-- pro_show_parentLst
DELIMITER $$ -- 调用过程输出父节点
DROP PROCEDURE IF EXISTS `pro_show_parentLst`$$ CREATE PROCEDURE `pro_show_parentLst`(IN rootId INT) BEGIN
DROP TEMPORARY TABLE IF EXISTS tmpLst; CREATE TEMPORARY TABLE IF NOT EXISTS tmpLst
(sno INT PRIMARY KEY AUTO_INCREMENT,id INT,depth INT);
CALL pro\_cre\_parentlist(rootId,0); SELECT channel.id,CONCAT(SPACE(tmpLst.depth*2),'--',channel.cname) NAME,channel.parent\_id,tmpLst.depth,fn\_tree_path(channel.id,'/') path,fn\_tree\_pathname(channel.id,'/') pathname FROM tmpLst,channel WHERE tmpLst.id=channel.id ORDER BY tmpLst.sno; END$$
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3，开始测试：
3.1，从根节点开始显示，显示子节点集合：
mysql> CALL pro_show_childLst(-1);
+----+-----------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+-----------------------+-----------+-------+-------------+----------------------------+
| 13 | --首页 | -1 | 1 | -1/13 | 首页/ |
| 16 | --左上幻灯片 | 13 | 2 | -1/13/16 | 首页/左上幻灯片/ |
| 14 | --TV580 | -1 | 1 | -1/14 | TV580/ |
| 17 | --帮忙 | 14 | 2 | -1/14/17 | TV580/帮忙/ |
| 18 | --栏目简介 | 17 | 3 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
| 15 | --生活580 | -1 | 1 | -1/15 | 生活580/ |
+----+-----------------------+-----------+-------+-------------+----------------------------+
6 rows in set (0.05 sec)
Query OK, 0 rows affected (0.05 sec)
3.2，显示首页下面的子节点
CALL pro_show_childLst(13);
mysql> CALL pro_show_childLst(13);
+----+---------------------+-----------+-------+----------+-------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+---------------------+-----------+-------+----------+-------------------------+
| 13 | --首页 | -1 | 0 | -1/13 | 首页/ |
| 16 | --左上幻灯片 | 13 | 1 | -1/13/16 | 首页/左上幻灯片/ |
+----+---------------------+-----------+-------+----------+-------------------------+
2 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.3，显示TV580下面的所有子节点
CALL pro_show_childLst(14);
mysql> CALL pro_show_childLst(14);
+----+--------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+--------------------+-----------+-------+-------------+----------------------------+
| 14 | --TV580 | -1 | 0 | -1/14 | TV580/ |
| 17 | --帮忙 | 14 | 1 | -1/14/17 | TV580/帮忙/ |
| 18 | --栏目简介 | 17 | 2 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
+----+--------------------+-----------+-------+-------------+----------------------------+
3 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.4，“帮忙”节点有一个子节点，显示出来：
CALL pro_show_childLst(17);
mysql> CALL pro_show_childLst(17);
+----+------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+------------------+-----------+-------+-------------+----------------------------+
| 17 | --帮忙 | 14 | 0 | -1/14/17 | TV580/帮忙/ |
| 18 | --栏目简介 | 17 | 1 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
+----+------------------+-----------+-------+-------------+----------------------------+
2 rows in set (0.03 sec)
Query OK, 0 rows affected (0.03 sec)
mysql>
3.5，“栏目简介”没有子节点，所以只显示最终节点：
mysql> CALL pro_show_childLst(18);
+----+----------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+----------------+-----------+-------+-------------+----------------------------+
| 18 | --栏目简介 | 17 | 0 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
+----+----------------+-----------+-------+-------------+----------------------------+
1 row in set (0.36 sec)
Query OK, 0 rows affected (0.36 sec)
mysql>
3.6，显示根节点的父节点
CALL pro_show_parentLst(-1);
mysql> CALL pro_show_parentLst(-1);
Empty set (0.01 sec)
Query OK, 0 rows affected (0.01 sec)
mysql>
3.7，显示“首页”的父节点
CALL pro_show_parentLst(13);
mysql> CALL pro_show_parentLst(13);
+----+----------+-----------+-------+-------+----------+
| id | NAME | parent_id | depth | path | pathname |
+----+----------+-----------+-------+-------+----------+
| 13 | --首页 | -1 | 0 | -1/13 | 首页/ |
+----+----------+-----------+-------+-------+----------+
1 row in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.8，显示“TV580”的父节点，parent_id为-1
CALL pro_show_parentLst(14);
mysql> CALL pro_show_parentLst(14);
+----+---------+-----------+-------+-------+----------+
| id | NAME | parent_id | depth | path | pathname |
+----+---------+-----------+-------+-------+----------+
| 14 | --TV580 | -1 | 0 | -1/14 | TV580/ |
+----+---------+-----------+-------+-------+----------+
1 row in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
3.9，显示“帮忙”节点的父节点
mysql>
CALL pro_show_parentLst(17);
mysql> CALL pro_show_parentLst(17);
+----+-----------+-----------+-------+----------+---------------+
| id | NAME | parent_id | depth | path | pathname |
+----+-----------+-----------+-------+----------+---------------+
| 17 | --帮忙 | 14 | 0 | -1/14/17 | TV580/帮忙/ |
| 14 | --TV580 | -1 | 1 | -1/14 | TV580/ |
+----+-----------+-----------+-------+----------+---------------+
2 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.10，显示最低层节点“栏目简介”的父节点
CALL pro_show_parentLst(18);
mysql> CALL pro_show_parentLst(18);
+----+----------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+----------------+-----------+-------+-------------+----------------------------+
| 18 | --栏目简介 | 17 | 0 | -1/14/17/18 | TV580/帮忙/栏目简介/ |
| 17 | --帮忙 | 14 | 1 | -1/14/17 | TV580/帮忙/ |
| 14 | --TV580 | -1 | 2 | -1/14 | TV580/ |
+----+----------------+-----------+-------+-------------+----------------------------+
3 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
参考网址：
http://jan.kneschke.de/projects/mysql/sp/sp_tree.sql
http://blog.csdn.net/ylqmf/article/details/5172901
- *
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Original url: Access
Created at: 2020-03-16 17:18:01
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