php无限归类

php无限分类
db设计：

CREATE TABLE IF NOT EXISTS `test` (	`id` INT(1) NOT NULL AUTO_INCREMENT,	`path` VARCHAR(255) NOT NULL,	`name` VARCHAR(255) NOT NULL,	PRIMARY KEY (`id`))ENGINE = MYISAM DEFAULT CHAR SET ='utf8';	INSERT INTO `test` VALUES 	('', '0', '公司'),	('', '0-1', '部门一'),	('', '0-2', '部门二'),	('', '0-3', '部门三'),	('', '0-1-1', '小组一'),	('', '0-1-2', '小组二'),	('', '0-2-1', '小组三'),	('', '0-2-2', '小组四');

php代码实现：

<?php$db = mysql_connect('localhost', 'root', 'zhw') or die('could not conenct to db');mysql_query("SET charset 'utf8'");mysql_select_db('test', $db);$query = mysql_query("SELECT `id`, concat(`path`, '-', id) AS pwd, `name` FROM `test` ORDER BY `pwd`");while ($row = mysql_fetch_array($query)){	$indent = str_repeat('    ', count(explode('-', $row['pwd'])) - 2);	$option .= "<option value='{$row['id']}'>{$indent}{$row['name']}</option>";}echo "<select>{$option}</select>";