Online PHP editor | output for dKZOU

<?php define('DB_HOST','localhost'); define('DB_NAME','client_registration'); define('DB_USER','root'); define('DB_PASSWORD','lunaone'); $con=new mysqli('localhost','root','password') or die("Failed to connect to MySQL: " . mysqli_error()); $db=mysqli_select_db('client_registration',$con) or die("Failed to connect to MySQL: " . mysqli_error()); function NewUser() { $firstName = $_POST['first_name']; $lastName = $_POST['last_name']; $companyName = $_POST['company_name']; $phoneNumber = $_POST['phone_number']; $email = $_POST['email_address']; $password = $_POST['password']; $query = "INSERT INTO WebsiteUsers (firstName,lastName,companyName,phoneNumber,email_address,password) VALUES ('$irstName','$lastName''$companyName','$phoneNumber','$email_address','$password')"; $data = mysqli_query ($query)or die(mysqli_error()); if($data) { echo "YOUR REGISTRATION IS COMPLETED..."; } } function SignUp() { if(!empty($_POST['user'])) //checking the 'user' name which is from Sign-Up.html, is it empty or have some text { $query = mysqli_query("SELECT * FROM WebsiteUsers WHERE email_address = '$_POST[email_address]' AND password = '$_POST[password]'") or die(mysqli_error()); if(!$row = mysqli_fetch_array($query) or die(mysqli_error())) { newuser(); } else { echo "SORRY...YOU ARE ALREADY REGISTERED USER..."; } } } if(isset($_POST['submit'])) { SignUp(); } ?>