一、数据库设计

--  -- Table structure for table `category` --   CREATE TABLE `category` (  `id` int(11) NOT NULL auto_increment,  `catpath` varchar(255) default NULL,  `name` varchar(255) default NULL,  PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=11 ;  --  -- Dumping data for table `category` --   INSERT INTO `category` VALUES (1, "0", "网站首页"); INSERT INTO `category` VALUES (2, "0-1", "Linux OS"); INSERT INTO `category` VALUES (3, "0-1", "Apache服务器"); INSERT INTO `category` VALUES (4, "0-1", "MySQL数据库"); INSERT INTO `category` VALUES (5, "0-1", "PHP脚本语言"); INSERT INTO `category` VALUES (6, "0-1-2", "Linux 系统教程"); INSERT INTO `category` VALUES (7, "0-1-2", "Linux 网络技术"); INSERT INTO `category` VALUES (8, "0-1-2", "Linux 安全基础"); INSERT INTO `category` VALUES (9, "0-1-2-7", "Linux LAMP"); INSERT INTO `category` VALUES (10, "0-1-3-10", "apache Server");  

这里说明下，catpath的-链接符号不是固定的，可以选择,；等特殊符号。

二、PHP代码实现

<? $conn = mysql_connect ( "localhost", "root", "root" ); mysql_select_db ( "test", $conn ); mysql_query ( "set names UTF8" ); $sql = "select id,concat(catpath,"-",id) as abspath,name from category order by abspath"; $query = mysql_query ( $sql ); while ( $row = mysql_fetch_array ( $query ) )  {   //第一种展示方法   //$space = str_repeat ( "    ", count ( explode ( "-", $row ["abspath"] ) ) - 1 );   //echo $space . $row ["name"] . "<br>";*/      //第二种展示方法   $space = str_repeat ( "    ", count ( explode ( "-", $row ["abspath"] ) ) - 1 );   $option .= "<option value="" . $row ["id"] . "">" . $space . $row ["name"] . "</option>"; } echo "<select name="opt">" . $option . "</select>"; ?> 

MySQL concat函数可以连接一个或者多个字符串

select concat("颜","培","攀")select `id`,`name`,concat(`id`,"-",`name`) as iname

以上就是本文的全部内容，介绍了php使用concat实现无线分类，希望对大家的学习有所帮助。