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>' . $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