删除无限分类并同时删除它下面的所有子分类的方法

$act = isset ($_GET['act']) ? trim ($_GET['act']) : "; 
if ($act == 'del') 
{ 
$sort_id = isset ($_GET['id']) ? intval($_GET['id']) : '0' ; 
$sort_ids = $sort_id; 
$childrenIds = getChildrenIds ($sort_id); 
if (!empty ($childrenIds)) 
{ 
$sort_ids .= $childrenIds; 
} 
$sql = “delete from `article_sort` WHERE `sort_id` in ({$sort_ids})"; 
$res = mysql_query ($sql); 
if ($res) 
{ 
alert ('删除成功'); 
exit; 
} 
else 
{ 
alert ('删除失败'); 
exit; 
} 
}

/*—————————————————— */ 
//– 获取无限分类ID下面的子类ID集 
//– $sort_id = $sort_id.getChildrenIds($sort_id); 
//– $sql = " ….. where sort_id in ($sort_id)"; 
/*—————————————————— */ 
function getChildrenIds ($sort_id) 
{ 
global $db; 
$ids = "; 
$sql = "SELECT * FROM ".$db->table('article_sort')." WHERE `parent_id` = '{$sort_id}'"; 
$res = $db->query ($sql); 
if ($res) 
{ 
while ($row = $db->fetch_assoc ($res)) 
{ 
$ids .= ','.$row['sort_id']; 
$ids .= getChildrenIds ($row['sort_id']); 
} 
} 
return $ids; 
}