<?php
function getChildren($cat) {
	$ret = array();
	$query = mysql_query("SELECT cat_id FROM cubecartstore_category where cat_father_id IN (".$cat.")");
	if ($query = false) {
		die('SQL ERROR');
	}
	$kids = array();
	while($children = mysql_fetch_array($query,MYSQL_ASSOC)) {
		$kids[] = $children['cat_id'];
	}

	if (count($kids) > 0) {
		$searchids = implode(',',$kids);
		$ret = $ret + getChild($searchids);
	}

	return $ret;

}

print_r(getChildren(0));
?>