Update points of a user in mysql database using php : <p>I am trying to take a string username from my android app and use that username to add 5 points to that specific users account.</p>

<pre><code>Example: 
My database now: user_id  name  username  password  points
                    1     test    test      test      0 

What I want:     user_id  name  username  password  points
                    1     test    test      test      5
</code></pre>

<p>Here is the php code I'm using right now, something must be wrong with it:</p>

<pre><code>&lt;?php
$con = mysqli_connect("localhost", "id177667_root", "***", "id177667_loginb");
$username = $_POST["username"];
$sql = "UPDATE user ". "SET points = points + 5 ". "WHERE username = $username" ;
$response = mysqli_query($sql, $con);
?&gt;
</code></pre>
