No UPDATE

The login_update.php code:


<?php include "db.php";?>
<?php include "functions.php"; ?>

<?php if(isset($_POST['submit'])){

$username = $_POST['username'];
$password = $_POST['password'];
$id = $_POST['id'];

    $query = "UPDATE users SET ";
    $query .= "username = '$username', ";
    $query .= "password = '$password' ";
    $query .= "WHERE id = $id"; //fara '' pt ca id in baza de date e integer

        $result = mysqli_query($connection, $querry);

            if(!$result) {

                die('Nu a trecut querry!'. mysqli_error($connection));
            }

}

?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
</head>
<body>

<div class="container">

    <div class="col-sm-6">
      <form action = "login_create.php" method = "post">

           <div class="form-group">
           <label for="username"><b>Username</b></label>
           <input type="text" class="form-control" name = "username">
           </div>

           <div class="form-group">
           <label for="password"><b>Password</b></label>
           <input type="password" class="form-control" name = "password">
           </div>

            <div class="form-group">
           <select name="id" id="">


            <?php
               showAllData();
            ?>


             </select>
           </div>

            <div class="form-group">
           <label for="submit"></label>
           <input type="submit" class="btn-primary" name = "submit" value = "UPDATE">
           </div>

        </form>
    </div>

</div>


</body>
</html>


The db.php code:

 <?php

   $connection = mysqli_connect('localhost', 'root', '', 'loginapp');

    if(!$connection) {

        die ('No database connection');
    }


?>


The functions.php code:


<?php include 'db.php'; ?>

<?php


   function showAllData(){

       global $connection;

       $query = "SELECT * FROM users";
       $result = mysqli_query($connection, $query);

            if(!$result){
                die ("Query failed!" . mysqli_error());}

            while($row = mysqli_fetch_assoc($result)){

                $id = $row['id'];

                    echo "<option value='$id'>$id</option>";

         }

    }

?>