$check = mysql_query("SELECT * FROM player_stages WHERE fid = '$userid' AND stage_id = '$level'", $db);
$checkRows = mysql_num_rows($check);
mail('dhtravlos@gmail.com', 'rows', $checkRows);
if ($checkRows > 0) {
    $row = mysql_fetch_array($checkh);
    if ($row['score'] < $score) {
        $update = mysql_query("UPDATE player_stages SET score = $score WHERE stage_id='$level' AND fid='$userid'", $db);
        if (!$update)
            mail('dhtravlos@gmail.com', 'error update', mysql_error());
    }
} elseif($checkRows == 0) {
    $insert = mysql_query("INSERT INTO player_stages (fid, score, stage_id) VALUES ('$userid', $score, '$level')", $db);
    if(!$insert)
        mail('dhtravlos@gmail.com', 'error insert', mysql_error());
} else {
    return true;
}