mysql - select - troppo tempo

[aquatimer2000]

non ho capito le parti in grassetto del seguente codice:

$query = mysql_unbuffered_query("SELECT nome,codice FROM tabella ORDER BY id", $db);
while(at$r = mysql_fetch_row($query))
	$select .= '<option value="'.$r[1].'">'.$r[0].'</option>';
$select .= '</select>';