在Mysql数据库里通过存储过程实现树形的遍历

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