seřazení dat v dotazu

 $query = "SELECT p.nazev_cz, p.nazev_en, p.id, p.kusu_skladem, p.aktivni,
	 
	 					CASE WHEN o.datum2 = 0 THEN DATEDIFF(0000000000,FROM_UNIXTIME(max(o.datum2))) 
						ELSE DATEDIFF(now(),FROM_UNIXTIME(max(o.datum2)))  END AS pocet_dnu
	 
	 
	 
                  	                        FROM produkty p
		 				JOIN vyrobci v  ON v.id_vyrobce=p.id_vyrobce
						LEFT JOIN objednavky_polozky op ON op.id_produkt = p.id 
						LEFT JOIN objednavky o ON o.id_objednavka = op.id_objednavka 
						WHERE v.id_vyrobce='$id_vyrobce' 
                                                ".$where."
		 				GROUP BY p.id
						ORDER BY ".$order_by_sql.", p.nazev_cz";

while($row = mysql_fetch_array($result))  {
		  if ( $row['pocet_dnu'] == '') {
		  		echo '<td class="right">-</td>';
		  } else {
		  		echo '<td class="right">'. $row['pocet_dnu'].'</td>';
		  }