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）

1，建立测试表和数据：

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;

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

-- 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$$

2.2，从某节点向上追溯根节点，递归生成临时表数据

-- 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$$

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

-- 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 ;

2.4，递归过程输出某节点name路径

-- 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 ;

2.5，调用函数输出id路径

-- 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$$

2.6，调用函数输出name路径

-- fn_tree_pathname
-- 调用函数

2.7，调用过程输出子节点

-- pro_show_childLst 
DELIMITER $$
-- 调用过程

2.8，调用过程输出父节点

-- pro_show_parentLst
DELIMITER $$
-- 调用过程

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>