php+mysql无限分类设计方法，非递归

CREATE TABLE IF NOT EXISTS `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 ;

INSERT INTO `category` (`id`, `catpath`, `name`) VALUES
(1, '0', '网站首页'),
(2, '0-1', 'Linux OS'),
(3, '0-1', 'Apache服务器'),
(4, '0-1', 'MySQL数据库'),
(5, '0-1', 'PHP脚本语言'),
(6, '0-1-2', 'Linux 系统教程'),
(7, '0-1-2', 'Linux 网络技术'),
(8, '0-1-2', 'Linux 安全基础'),
(9, '0-1-2-7', 'Linux LAMP'),
(10, '0-1-3-10', 'apache Server');

$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'] . '
';*/
/**
 第二种展示方法
*/
$space = str_repeat ( '——', count ( explode ( '-', $row ['abspath'] ) ) - 1 );
$option .= '' . $space . $row ['name'] . '<Br>';
}
echo $option;
exit();
echo '<select name="opt">' . $option . '</select>';