Can anyone help me? I want to make this code work. If the variable $result is empty, I want it to echo "Login Failed." and if it isn't, I want it to echo "Login Successful."

Login Form

<html>
<head>
<title> Student Log In </title>
</head>
<body>

<form action="studentloggedin.php" method="post">
User Number: <input type="integer" name="User_Number" />
Password: <input type="password" name="Password" /></br></br>
<input type="submit" />
</form>

</body>
</html>

Checker for Username and Password in the linked Database

<?php

$con = mysql_connect("localhost","root","usbw");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}

$usernumber = $_POST['User_Number'];
$password = $_POST['Password'];


mysql_select_db("ict_helpdesk", $con);

$result = mysql_query("SELECT * FROM students WHERE students.user_number = $usernumber and WHERE students.password = $password");

if ($result = "")
echo "Login Failed.";
else
echo "Login Successful.";

?>