tjek blob felt i db

Hvordan tjekker jo om et felt i database er tomt ???


function display_thumb($id){
    $db = mysql_connect( $dbServer, $dbUser, $dbPass) or die("Couldn't connect to database server");
      mysql_select_db( $dbDatabase, $db) or die ("Could not open database");

  $result1 = mysql_query("SELECT * FROM binary_data WHERE id = '$id' ",$db);
  while ($row1 = mysql_fetch_array($result1))
{

if(empty($row1["picture"])) {
  $say_what = 1;
} else {
  $say_what = 2;
}

if($say_wat == '2') {
  $say_wat = "Tom";
} else {
  $say_wat = "Fuld";
}


return $say_wat;
}

}


Den giver ikke noget i $say_wat hvis feltet er tomt ??? HJÆLP....