下面一段代码是创建相应数据库的sql代码：
复制代码 代码如下:
//////////////
//////无限分类的数据库设计及样例
//////////////
mysql> create database db_kind;
Query OK, 1 row affected
mysql> use db_kind;
Database changed
mysql> create table tb_kind(
-> id int not null auto_increment primary key,
-> pid int,
-> path varchar(200)
-> );
Query OK, 0 rows affected
mysql> insert into tb_kind values(null,"新闻",0,0);
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"视频",0,0);
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"图片",0,0);
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"博客",0,0);
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"体育新闻",1,"0-1");
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"娱乐新闻",1,"0-1");
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"财经新闻",1,"0-1");
Query OK, 1 row affected
mysql> select * from db_kind;
ERROR 1146 : Table 'db_kind.db_kind' doesnot exist
mysql> select * from tb
_kind;
+----+----------+-----+------+
| id | pname | pid | path |
+----+----------+-----+------+
| 1 | 新闻 | 0 | 0 |
| 2 | 视频 | 0 | 0 |
| 3 | 图片 | 0 | 0 |
| 4 | 博客 | 0 | 0 |
| 5 | 体育新闻 | 1 | 0-1 |
| 6 | 娱乐新闻 | 1 | 0-1 |
| 7 | 财经新闻 | 1 | 0-1 |
+----+----------+-----+------+
7 rows in set
mysql> insert into tb_kind values(null,"篮球新闻",5,"0-1-5");
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"足球新闻",5,"0-1-5");
Query OK, 1 row affected
mysql> select * from tb_kind;
+----+----------+-----+-------+
| id | pname | pid | path |
+----+----------+-----+-------+
| 1 | 新闻 | 0 | 0 |
| 2 | 视频 | 0 | 0 |
| 3 | 图片 | 0 | 0 |
| 4 | 博客 | 0 | 0 |
| 5 | 体育新闻 | 1 | 0-1 |
| 6 | 娱乐新闻 | 1 | 0-1 |
| 7 | 财经新闻 | 1 | 0-1 |
| 8 | 篮球新闻 | 5 | 0-1-5 |
| 9 | 足球新闻 | 5 | 0-1-5 |
+----+----------+-----+-------+
9 rows in set
mysql> insert into tb_kind values(null,"NBA",8,"0-1-5-8");
Query OK, 1 row affected
mysql> insert into tb_kind values(null,"CBA",8,"0-1-5-8");
Query OK, 1 row affected
mysql> select * from tb_kind;
+----+----------+-----+---------+
| id | pname | pid | path |
+----+----------+-----+---------+
| 1 | 新闻 | 0 | 0 |
| 2 | 视频 | 0 | 0 |
| 3 | 图片 | 0 | 0 |
| 4 | 博客 | 0 | 0 |
| 5 | 体育新闻 | 1 | 0-1 |
| 6 | 娱乐新闻 | 1 | 0-1 |
| 7 | 财经新闻 | 1 | 0-1 |
| 8 | 篮球新闻 | 5 | 0-1-5 |
| 9 | 足球新闻 | 5 | 0-1-5 |
| 10 | NBA | 8 | 0-1-5-8 |
| 11 | CBA | 8 | 0-1-5-8 |
+----+----------+-----+---------+
11 rows in set
mysql> select concat(path,"-",id) from tb_kind;
+---------------------+
| concat(path,"-",id) |
+---------------------+
| 0-1 |
| 0-2 |
| 0-3 |
| 0-4 |
| 0-1-5 |
| 0-1-6 |
| 0-1-7 |
| 0-1-5-8 |
| 0-1-5-9 |
| 0-1-5-8-10 |
| 0-1-5-8-11 |
+---------------------+
11 rows in set
mysql> select concat(path,"-",id) from tb_kind;
+---------------------+
| concat(path,"-",id) |
+---------------------+
| 0-1 |
| 0-2 |
| 0-3 |
| 0-4 |
| 0-1-5 |
| 0-1-6 |
| 0-1-7 |
| 0-1-5-8 |
| 0-1-5-9 |
| 0-1-5-8-10 |
| 0-1-5-8-11 |
+---------------------+
11 rows in set
mysql> select concat(path,"-",id) as abs from tb_kind order by abs.path;
ERROR 1054 : Unknown column 'abs.path' in 'order clause'
mysql> select concat(path,"-",id) as abs from tb_kind order by abs
+------------+
| abs |
+------------+
| 0-1 |
| 0-1-5 |
| 0-1-5-8 |
| 0-1-5-8-10 |
| 0-1-5-8-11 |
| 0-1-5-9 |
| 0-1-6 |
| 0-1-7 |
| 0-2 |
| 0-3 |
| 0-4 |
+------------+
11 rows in set
mysql> select concat(path,"-",id) as,id,name,path abs from tb_kind order by abs;
ERROR 1064 : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'id,name,path abs from tb_kind order by abs' at line 1
mysql> select concat(path,"-",id) as abs,
id,pname,path abs from tb_kind order by abs;
+------------+----+----------+---------+
| abs | id | pname | abs |
+------------+----+----------+---------+
| 0-1 | 1 | 新闻 | 0 |
| 0-1-5 | 5 | 体育新闻 | 0-1 |
| 0-1-5-8 | 8 | 篮球新闻 | 0-1-5 |
| 0-1-5-8-10 | 10 | NBA | 0-1-5-8 |
| 0-1-5-8-11 | 11 | CBA | 0-1-5-8 |
| 0-1-5-9 | 9 | 足球新闻 | 0-1-5 |
| 0-1-6 | 6 | 娱乐新闻 | 0-1 |
| 0-1-7 | 7 | 财经新闻 | 0-1 |
| 0-2 | 2 | 视频 | 0 |
| 0-3 | 3 | 图片 | 0 |
| 0-4 | 4 | 博客 | 0 |
+------------+----+----------+---------+
11 rows in set
mysql>
下面是php源文件：
复制代码 代码如下:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
<body>
<!--显示结果
新闻
体育新闻
篮球新闻
NBA
CBA
足球新闻
娱乐新闻
财经新闻
视频
图片
博客
-->
<?
$conn=mysql_connect("localhost","root","root");
mysql_select_db("db_kind");
mysql_query("set names utf8");
$sql="select concat(path,'-',id) as abspath,id,pname,path from tb_kind order by abspath";
$rs=mysql_query($sql);
while($result=mysql_fetch_assoc($rs)){
$num=count(explode("-",$result[path]))-1;
$new_str=str_repeat("---",$num);
echo $new_str.$result[pname];
echo "<br>";
}
$str=str_repeat("=",10);
echo $str;
$num=count(explode("-","0-1-5-8"))-1;
echo $num;
?>
</body>
</html>
上面的代码中其实中间有空格的输入效果还是非常不错的，请大家本地测试。因编辑器问题导致排版混乱。
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