One way of detecting of a select statement returned any results.  Using this currently…

  $result = mysql_query(“SELECT * FROM some_table where some_field = ’some_value’ “, $connection);

  if (!$result) 
    $count=0;
  else
    $count =mysql_num_rows($result);

  if ($count == 0) {
   die(“Database query failed: ” . mysql_error());