我沒有收到Mysql錯誤，但查詢不起作用

我正在爲PHP創建一個簡單的登錄腳本，但我沒有收到錯誤或任何內容，但由於某種原因，此查詢不起作用。這從來沒有發生過我，我現在感到沮喪。我沒有收到Mysql錯誤，但查詢不起作用

這是php_classes文件：

<?php 

    //Database Connection 
    $database_host = "localhost"; 
    $database_user = "root"; 
    $database_pass = "**PASSWORD**"; 
    $database_name = "XoticSite"; 

    $database_connection = mysqli_connect($database_host,               $database_user, $database_pass, $database_name); 
    if($database_connection){ 
    echo("Connection Works!!! <br />"); 
    } 






    //userclass 
    class User 
    { 



public function __construct() 
{ 
    #global vars 

    $username = null; 
    $password = null; 
    $fname = null; 
    $lname = null; 
    $email = null; 
    $privilege = null; 
    $profilePath = null; 
    $trys = 0; 

    #*******# 
} 
public function checkLogin($db){ 
    $userQuery = mysqli_query($db, "SELECT * FROM `Users` WHERE 
          `username`='$username' && `password`='$password' LIMIT 1") or die("MYSQL ERROR"); 
    if(mysqli_num_rows($userQuerry) == 1){ 
     $userArray = mysqli_fetch_array($userQuery); 

     $fname = $userArray['fname']; 
     $lname = $userArray['lname']; 
     $email = $userArray['email']; 
     $ip = $userArray['ip']; 
     $privilege = $userArray['privilege']; 
     $profile = $userArray['profile']; 

     return true; 
    } 
    else{ 
     return false; 
    } 


} 
public function setData($u, $p){ 
    $username = $u; 
    $password = $p; 
    echo $username . $password; 
} 
public function getData($x){ 
    if($x == 1){ 
     return $username; 
    } 
    if($x == 2){ 
     return $password; 
    } 
    if($x == 3){ 
     return $trys; 
    } else{ 
     return false; 
     } 
    } 
    } 

    //Client 
    if(!isset($_SESSION['ClientUser'])){ 
     session_start(); 
     echo "Created User"; 
     $_SESSION['ClientUser'] = new User; 
    } 
    ?>

這是test.php的類：

<?php 
    include_once 'php_includes/php_classes.php'; 

    $_SESSION['ClientUser']->setData("username", "12345"); 
    if($_SESSION['ClientUser']->checkLogin($database_connection)){ 
     echo "Login Success"; 
    } else{ 
     echo "Login Fail"; 
     echo $_SESSION['ClientUser']->username; 
    } 
?> 

<html lang='en'> 

    <head> 
     <title>Test</title> 
     <meta charset="UTF-8"> 
     <link rel="stylesheet" type="text/css" href="style.css"> 

     <script type="text/javascript"> 

     </script> 
    </head> 
    <body> 
     <div id="mainWrapper"> 
      <?php 
       include_once("php_templates/header.php"); 
      ?> 
      <div id="body"> 

      </div> 
      <?php 
       include_once("php_templates/footer.php"); 
      ?> 
     </div> 
    </body> 

</html>

每當我跑的測試，我總是登錄失敗，這shold不會發生，因爲我有數據庫中的用戶名和密碼：

Picture of the Table in the Database

我在LAMP上運行這個，特別是Ubuntu 15.10

來源

2016-11-01 Jesus Velarde