在Mysql数据库里通过存储过程实现树形的遍历

时间:2020-12-15 人气:0

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，下面给大家介绍在Mysql数据库里通过存储过程实现树形的遍历，一起看看吧

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。

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
DROP PROCEDURE IF EXISTS csdn.pro_cre_childlist
CREATE PROCEDURE csdn.pro_cre_childlist(IN rootId INT,IN nDepth INT)
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;

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
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;

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
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; 
DELIMITER ;

2.4，递归过程输出某节点name路径

-- pro_cre_pnlist
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; 
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 ;

2.7，调用过程输出子节点

-- 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

2.8，调用过程输出父节点

-- 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

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

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>

以上所述是小编给大家介绍的在Mysql数据库里通过存储过程实现树形的遍历，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！

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