if($this->ChannelUnit->ChannelInfos['issystem']!=-1)

$query = "Select arc.*,tp.reid,tp.typedir,ch.addtable 
from `dede_archives` arc 
left join dede_arctype tp on tp.id=arc.typeid 
left join dede_channeltype as ch on arc.channel = ch.id 
where arc.id='$aid' "; 
$this->Fields = $this->dsql->GetOne($query);

$query = "Select arc.*,tp.reid,tp.typedir,tp.typeimg,ch.addtable 
from `dede_archives` arc 
left join dede_arctype tp on tp.id=arc.typeid 
left join dede_channeltype as ch on arc.channel = ch.id 
where arc.id='$aid' "; 
$this->Fields = $this->dsql->GetOne($query);