mysql层级查询在一列显示 mysql查询层级菜单

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mob64ca1419a401 2024-03-12 14:56:42

文章标签 mysql层级查询在一列显示 mysql 子节点递归 文章分类 MySQL 数据库

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。

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
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>

转自： http://blog.itpub.net/26230597/viewspace-1269668/

在Oracle 中我们知道有一个 Hierarchical Queries 通过CONNECT BY 我们可以方便的查了所有当前节点下的所有子节点。但很遗憾，在MySQL的目前版本中还没有对应的功能。

在MySQL中如果是有限的层次，比如我们事先如果可以确定这个树的最大深度是4, 那么所有节点为根的树的深度均不会超过4，则我们可以直接通过left join 来实现。

但很多时候我们无法控制树的深度。这时就需要在MySQL中用存储过程来实现或在你的程序中来实现这个递归。本文讨论一下几种实现的方法。

样例数据：

mysql> create table treeNodes 15 | +----+----------+------+ 17 rows in set (0.00 sec)

树形图如下

+-- 11:K

方法一：利用函数来得到所有子节点号。

创建一个function getChildLst, 得到一个由所有子节点号组成的字符串.

mysql> delimiter // mysql> mysql> CREATE FUNCTION `getChildLst`(rootId INT) -> // Query OK, 0 rows affected (0.00 sec)
mysql> mysql> delimiter ;

使用我们直接利用find_in_set函数配合这个getChildlst来查找

mysql> select getChildLst(1); +-----------------+ | getChildLst(1)  | +-----------------+ | $,1,2,3,4,5,6,7 | +-----------------+ 1 row in set (0.00 sec)
mysql> select * from treeNodes   6 | +----+----------+------+ 7 rows in set (0.01 sec)
mysql> select * from treeNodes   6 | +----+----------+------+ 3 rows in set (0.01 sec)

优点: 简单，方便，没有递归调用层次深度的限制 (max_sp_recursion_depth,最大255) ；

缺点：长度受限，虽然可以扩大 RETURNS varchar(1000)，但总是有最大限制的。

MySQL目前版本( 5.1.33-community)中还不支持function 的递归调用。

方法二：利用临时表和过程递归

创建存储过程如下。createChildLst 为递归过程，showChildLst为调用入口过程，准备临时表及初始化。

mysql> delimiter // mysql> mysql> # -> // Query OK, 0 rows affected (0.00 sec)
mysql> mysql> # -> insert into tmpLst values (null,rootId,nDepth);

-> // Query OK, 0 rows affected (0.00 sec) mysql> delimiter ;

调用时传入结点

mysql> call showChildLst(1); +-----+------+-------+----+----------+------+ | sno | id 6 | +-----+------+-------+----+----------+------+

7 rows in set (0.13 sec)
Query OK, 0 rows affected, 1 warning (0.14 sec)
mysql> mysql> call showChildLst(3); +-----+------+-------+----+----------+------+ | sno | id 6 | +-----+------+-------+----+----------+------+

3 rows in set (0.11 sec)
Query OK, 0 rows affected, 1 warning (0.11 sec)

depth 为深度，这样可以在程序进行一些显示上的格式化处理。类似于oracle中的 level 伪列。sno 仅供排序控制。这样你还可以通过临时表tmpLst与数据库中其它表进行联接查询。

MySQL中你可以利用系统参数 max_sp_recursion_depth 来控制递归调用的层数上限。如下例设为12.

mysql> set max_sp_recursion_depth=12; Query OK, 0 rows affected (0.00 sec)

优点 : 可以更灵活处理，及层数的显示。并且可以按照树的遍历顺序得到结果。

缺点 : 递归有255的限制。

方法三：利用中间表和过程

(本方法由yongyupost2000提供样子改编)

创建存储过程如下。由于MySQL中不允许在同一语句中对临时表多次引用，只以使用普通表tmpLst来实现了。当然你的程序中负责在用完后清除这个表。

delimiter //

drop PROCEDURE IF EXISTS showTreeNodes_yongyupost2000//

CREATE PROCEDURE showTreeNodes_yongyupost2000 (IN rootid INT) BEGIN DECLARE Level int ; drop TABLE IF EXISTS tmpLst; CREATE TABLE tmpLst ( id int, nLevel int, sCort varchar(8000) ); Set Level=0 ; INSERT into tmpLst SELECT id,Level,ID FROM treeNodes WHERE PID=rootid; WHILE ROW_COUNT()>0 DO SET Level=Level+1 ; INSERT into tmpLst SELECT A.ID,Level,concat(B.sCort,A.ID) FROM treeNodes A,tmpLst B WHERE A.PID=B.ID AND B.nLevel=Level-1 ; END WHILE; END; //

delimiter ;

CALL showTreeNodes_yongyupost2000(0);

执行完后会产生一个tmpLst表，nLevel 为节点深度，sCort 为排序字段。使用方法

SELECT concat(SPACE(B.nLevel*2),'+--',A.nodename) FROM treeNodes A,tmpLst B WHERE A.ID=B.ID ORDER BY B.sCort;

+--------------------------------------------+ | concat(SPACE(B.nLevel*2),'+--',A.nodename) | +--------------------------------------------+ | +--A | +--------------------------------------------+ 17 rows in set (0.00 sec)

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