關于多級別菜單欄或者權限系統中部門上下級的樹形遍歷，oracle中有connect by來實現，mysql沒有這樣的便捷途徑，所以MySQL遍歷數據表是我們經常會遇到的頭痛問題，下面通過存儲過程來實現。
1，建立測試表和數據：
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,'首頁',-1),
(14,'TV580',-1),
(15,'生活580',-1),
(16,'左上幻燈片',13),
(17,'幫忙',14),
(18,'欄目簡介',17);
DROP TABLE IF EXISTS channel;
2，利用臨時表和遞歸過程實現樹的遍歷（mysql的UDF不能遞歸調用）：
2.1，從某節點向下遍歷子節點，遞歸生成臨時表數據
-- 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，從某節點向上追溯根節點，遞歸生成臨時表數據
-- 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，實現類似Oracle SYS_CONNECT_BY_PATH的功能，遞歸過程輸出某節點id路徑
-- 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，遞歸過程輸出某節點name路徑
-- 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，調用函數輸出id路徑
-- 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，調用函數輸出name路徑
-- fn_tree_pathname
-- 調用函數輸出name路徑
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，調用過程輸出子節點
-- pro_show_childLst
DELIMITER
-- 調用過程輸出子節點
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，調用過程輸出父節點
-- pro_show_parentLst
DELIMITER
-- 調用過程輸出父節點
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，開始測試：
3.1，從根節點開始顯示，顯示子節點集合：
mysql> CALL pro_show_childLst(-1);
+----+-----------------------+-----------+-------+-------------+----------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+-----------------------+-----------+-------+-------------+----------------------------+
| 13 | --首頁 | -1 | 1 | -1/13 | 首頁/ |
| 16 | --左上幻燈片 | 13 | 2 | -1/13/16 | 首頁/左上幻燈片/ |
| 14 | --TV580 | -1 | 1 | -1/14 | TV580/ |
| 17 | --幫忙 | 14 | 2 | -1/14/17 | TV580/幫忙/ |
| 18 | --欄目簡介 | 17 | 3 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |
| 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，顯示首頁下面的子節點
CALL pro_show_childLst(13);
mysql> CALL pro_show_childLst(13);
+----+---------------------+-----------+-------+----------+-------------------------+
| id | NAME | parent_id | depth | path | pathname |
+----+---------------------+-----------+-------+----------+-------------------------+
| 13 | --首頁 | -1 | 0 | -1/13 | 首頁/ |
| 16 | --左上幻燈片 | 13 | 1 | -1/13/16 | 首頁/左上幻燈片/ |
+----+---------------------+-----------+-------+----------+-------------------------+
2 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.3，顯示TV580下面的所有子節點
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 | --幫忙 | 14 | 1 | -1/14/17 | TV580/幫忙/ |
| 18 | --欄目簡介 | 17 | 2 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |
3 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.4，“幫忙”節點有一個子節點，顯示出來：
CALL pro_show_childLst(17);
mysql> CALL pro_show_childLst(17);
| id | NAME | parent_id | depth | path | pathname |
| 17 | --幫忙 | 14 | 0 | -1/14/17 | TV580/幫忙/ |
| 18 | --欄目簡介 | 17 | 1 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |
2 rows in set (0.03 sec)
Query OK, 0 rows affected (0.03 sec)
mysql>
3.5，“欄目簡介”沒有子節點，所以只顯示最終節點：
mysql> CALL pro_show_childLst(18);
+--| id | NAME | parent_id | depth | path | pathname |
| 18 | --欄目簡介 | 17 | 0 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |
1 row in set (0.36 sec)
Query OK, 0 rows affected (0.36 sec)
mysql>
3.6，顯示根節點的父節點
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，顯示“首頁”的父節點
CALL pro_show_parentLst(13);
mysql> CALL pro_show_parentLst(13);
| id | NAME | parent_id | depth | path | pathname |
| 13 | --首頁 | -1 | 0 | -1/13 | 首頁/ |
1 row in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
3.8，顯示“TV580”的父節點，parent_id為-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，顯示“幫忙”節點的父節點
CALL pro_show_parentLst(17);
mysql> CALL pro_show_parentLst(17);
| id | NAME | parent_id | depth | path | pathname |
| 17 | --幫忙 | 14 | 0 | -1/14/17 | TV580/幫忙/ |
| 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，顯示最低層節點“欄目簡介”的父節點
CALL pro_show_parentLst(18);
mysql> CALL pro_show_parentLst(18);
| id | NAME | parent_id | depth | path | pathname |
| 18 | --欄目簡介 | 17 | 0 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |
| 17 | --幫忙 | 14 | 1 | -1/14/17 | TV580/幫忙/ |
| 14 | --TV580 | -1 | 2 | -1/14 | TV580/ |
3 rows in set (0.02 sec)
Query OK, 0 rows affected (0.02 sec)
mysql>
以上所述是小編給大家介紹的在Mysql數據庫里通過存儲過程實現樹形的遍歷，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對腳本之家網站的支持！
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