Anything wrong with this UPDATE query?

1 


    $label = htmlspecialchars(mysql_escape_string($_POST['labelClass']));
    
    $bib_id = htmlspecialchars(mysql_escape_string($_POST['bib_id']));
       
    $thing = substr($bib_id, 9);

    $sql = "UPDATE bibs SET labelClass = '$label' WHERE bib_id = '$thing'";
    $result = mysql_query($sql) or die(mysql_error());

seems ok to me, but it’s not working :S . I’ve also done it with locking and unlocking tables etc…too. still no dice.

any tips or advice, much appreciated. cheers.