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_childlistDROP PROCEDURE IF EXISTS csdn.pro_cre_childlistCREATE 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_parentlistDROP PROCEDURE IF EXISTS csdn.pro_cre_parentlistCREATE 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_pathlistUSE csdnDROP PROCEDURE IF EXISTS pro_cre_pathlistCREATE 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_pnlistUSE csdnDROP PROCEDURE IF EXISTS pro_cre_pnlistCREATE 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_pathDELIMITERDROP FUNCTION IF EXISTS csdn.fn_tree_pathCREATE 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 DELIMITERDROP FUNCTION IF EXISTS csdn.fn_tree_pathnameCREATE 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; ENDDELIMITER ;
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_childLstCREATE 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_parentLstDELIMITER-- 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！
