title: Calculate value of two columns using Laravel Query
body: <p>How can I calculate the value of two columns using Laravel 5 query?</p>
  
  <p>Example of my DB structure. </p>
  
  <pre><code>+--------+--------+
  | value1 | value2 |
  +--------+--------+
  | 30     | 30     |
  +--------+--------+
  | 10     | 10     |
  +--------+--------+
  | 5      | 25     |
  +--------+--------+
  </code></pre>
  
  <p>I want to get the total value of <code>value1 + value2</code> I've tried something like this, but it didn't work.</p>
  
  <pre><code>$topUsers = DB::table('users_stats')-&gt;orderBy('value1 '+' value2', 'desc')-&gt;limit(3)-&gt;get();
  </code></pre>
  
  <p>This way I get this error:</p>
  
  <pre><code>ErrorException in HomeController.php line 39:
  
  A non-numeric value encountered
  </code></pre>
  
  <p>Expected output:</p>
  
  <pre><code>60
  20
  30
  </code></pre>