なぜ機能しないのかわかりません...作成された変数を次のように「並べ替え」ようとしています:
mysql_query("SELECT *,DATE_FORMAT(FROM_UNIXTIME(banfrom), '%d/%m/%Y') as time FROM ab_list WHERE time = '24/08/2013' ORDER BY banfrom DESC LIMIT 0,50");
または、
$hr = date('d/m/Y');
mysql_query("SELECT *,DATE_FORMAT(FROM_UNIXTIME(banfrom), '%d/%m/%Y') as time FROM ab_list WHERE time = '$hr' ORDER BY banfrom DESC LIMIT 0,50");