dedecms channelartlist增加orderway实现倒序

$orderway=$ctag->GetAtt('orderway'); 
if(empty($orderway)) 
{ 
$orderway="asc"; 
} 

$dsql->SetQuery("Select id,typename,typedir,isdefault,ispart,defaultname,namerule2,moresite,siteurl,sitepath,typelitpic 
from `dede_arctype` where $tpsql order by sortrank $orderway limit $totalnum");