ชขอความช่วยเหลือเกี่ยวกับโค๊ด บันทึกข้อมูลลง sql หน่อยครับ

<?php
session_start();
include "../inc/configue.php";
$uname = $_POST["uname"];
$pword = $_POST["pword"];
$fullname = $_POST["fullname"];
$email = $_POST["email"];
$sql = "SELECT * FROM users WHERE uname='$uname' AND pword='$pword'";
$q = mysql_query($sql);
$r = mysql_fetch_array($q);
if($r)
{
    echo "Username already exists!";
}
else 
{
   $sql = "INSERT INTO users (uname,pword,fullname,email) VALUES ('$uname','$pword','$fullname','$email')";
  $q = mysql_query($sql);
  echo "Register Complete!<br>";
  echo "<br> Go to <a href='login.php'>Login page</a>";
}
mysql_close();
?>

<?php
$host = "localhost";
$username = "root";
$password = "";
$db = "mydb";
$conn = mysql_connect($host,$username,$password);
if(isset($conn)) {
  
} else {
  echo "Cannot connect server";
}
$selectdb = mysql_select_db($db,$conn);
if(isset($selectdb)) {
  
} else {
  echo "Cannot select database";
}
mysql_query("SET NAMES utf8");
?>