Nested List Mysql

<?php
/*
--
-- Database: `test`
--
-- --------------------------------------------------------
--
-- Table structure for table `nested_categories`
--
DROP TABLE IF EXISTS `nested_categories`;
CREATE TABLE IF NOT EXISTS `nested_categories` (
  `id_cat` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL,
  `lft` int(11) NOT NULL,
  `rgt` int(11) NOT NULL,
  PRIMARY KEY (`id_cat`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1;
--
-- Dumping data for table `nested_categories`
--
INSERT INTO `nested_categories` (`id_cat`, `name`, `lft`, `rgt`) VALUES
(1, 'Website', 1, 22),
(2, 'Database', 2, 9),
(3, 'Oracle', 3, 4),
(4, 'MySQL', 5, 6),
(5, 'SQL Server', 7, 8),
(6, 'Programming', 10, 19),
(7, 'JavaScript', 11, 14),
(8, 'jQuery', 12, 13),
(9, 'PHP', 15, 16),
(10, 'CSS', 17, 18),
(11, 'HTML', 20, 21);
*/
mysql_connect('localhost','root','');
mysql_select_db('test');
$sql="SELECT node.name, (COUNT( parent.name ) -1) AS depth
      FROM nested_categories AS node
        CROSS JOIN nested_categories AS parent
      WHERE node.lft BETWEEN parent.lft AND parent.rgt
      GROUP BY node.name
      ORDER BY node.lft";
$result = mysql_query($sql);
$tree = array();
while ($row = mysql_fetch_assoc($result)) {
    $tree[] = $row;
}
// Bootstrap loop
$result        = '';
$currDepth     = 0;
$lastNodeIndex = count($tree) - 1;
// Start the loop
foreach ($tree as $index => $currNode) {
    // Level down? (or the first)
    if ($currNode['depth'] > $currDepth || $index == 0) {
        $result .= '<ul>';
    }
    // Level up?
    if ($currNode['depth'] < $currDepth) {
        $result .= str_repeat('</ul></li>', $currDepth - $currNode['depth']);
    }
    // Always open a node
    $t = ($index == 0) ? 1 : 2;
    $result .= '<li>' . $currNode['name'];
    // Check if there's chidren
    if ($index != $lastNodeIndex && $tree[$index + 1]['depth'] <= $tree[$index]['depth']) {
        $result .= '</li>'; // If not, close the <li>
    }
    // Adjust current depth
    $currDepth = $currNode['depth'];
    // Are we finished?
    if ($index == $lastNodeIndex) {
        $result .= '</ul>' . str_repeat('</li></ul>', $currDepth);
    }
}

// Indent the code
// For UTF8: tidy_parse_string($result, array('indent' => true, 'show-body-only' => true), 'UTF8')
//$result = tidy_parse_string($result, array('indent' => true, 'show-body-only' => true));
print $result;