dedecms如何按照软件下载次数排列

dedecmsCMS的arclist标签可以按照文章点击次数、发布日期、得分等进行排序，今天有个客户需要按照软件下载次数进行排列，于是做了简单二次开发，首先找到include目录下面的taglib目录里的arclist.lib.php文件在376行后加入如下代码
 

 if($orderby == 'down')

 {

  $sql = "select SUM(downloads) as down_num,id from dede_downloads group by id ORDER BY down_num DESC LIMIT 0,15";

  $dsql->Execute('me',$sql);

  while($drow = $dsql->GetArray() )

  {

   $arr[] = $drow['id'];

  }

  $dstr = implode(",",$arr);

  if($orwhere!='')

  {

   $orwhere .= " AND arc.id in($dstr)";

  }else{

   $orwhere .= " where arc.id in($dstr)";

  }

  $ordersql = 'ORDER BY field(arc.id,'.$dstr.')';

 }