<?php
$username = $_POST['username'];
$email = $_POST['email'];
$password = $_POST['password'];

if (!empty($username) || !empty($email) || !empty($password)) {
    $host = "localhost";
    $dbUsername = "root";
    $dbPassword = "";
    $db = "coursework";
    //create connection
    $conn = new mysqli($host, $dbUsername, $dbPassword, $db);
    if (mysqli_connect_error()) {
     die('Connect Error('. mysqli_connect_errno().')'. mysqli_connect_error());
    } else {
     $SELECT = "SELECT email FROM users WHERE email = ? LIMIT 1";
     $INSERT = "INSERT INTO users (username, email, password) values(?, ?, ?)";
     //Prepare statement
     $stmt = $conn->prepare($SELECT);
     $stmt->bind_param("s", $email);
     $stmt->execute();
     $stmt->bind_result($email);
     $stmt->store_result();
     $rnum = $stmt->num_rows;
     if ($rnum==0) {
      $stmt->close();
      $stmt = $conn->prepare($INSERT);
      $stmt->bind_param("sss", $username, $email, $password);
      $stmt->execute();
      // echo "New record inserted sucessfully";
        header("location: login.php");

     } else {
      header("location: signup.php?msg=Registered");
     }
     $stmt->close();
     $conn->close();
    }
} else {
 echo "All field are required";
 die();
}
?>