php递归实现无限分类生成下拉列表的函数

/*—————————————————— */
//– 递归实现无限分类生成下拉列表函数
//– $tpl->assign(sort_list,createSortOptions ());
//– $tpl->assign(sort_list,createSortOptions ($sort_id));
/*—————————————————— */
function createSortOptions ($selected=0,$parent_id=0,$n=-1)
{
global $db;
$sql = "SELECT * FROM `@__article_sort` WHERE `parent_id` = {$parent_id}";
$options = ";
static $i = 0;
if ($i == 0)
{
$options .= <option value="0″ >请选择</option>;
}
$res = $db->query ($sql);
if ($res)
{
$n++;
while ($row = $db->fetch_assoc ($res))
{
$i++;
$options .="<option value={$row[sort_id]}";
if ($row[sort_id] == $selected)
{
$options .= selected ;
}
$options .=">".str_repeat( ,$n*3).$row[sort_name]."</option>\n";
$options .=createSortOptions ($selected,$row[sort_id],$n);
}
}
return $options;
}