title: database wont update after clicking submit button
body: <p>After connecting to the database, here is the simplest code that should update my database after clicking the submit button : </p>
  
  <pre><code>&lt;?php
  if (isset($_POST['update'])){
  $sql = "UPDATE accounts SET download='Yes' WHERE id=15 ";
  }
  
  ?&gt;
  
  &lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
  &lt;/head&gt;
  &lt;body&gt;
  
  &lt;form  method="post" &gt;  
  
    &lt;input type="submit" value="Update " name="update"&gt;
  &lt;/form&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>I dont know what am i doing wrong.</p>