title: Convert number to date in PHP and format to YYYYMMDD
body: <p>I want to convert date from, for example, 1441065600 to <code>YYYYMMDD</code> format. How do I do that?</p>
  
  <pre><code>$temp = date("Y-m-d",1441065600);
  $rel_date = date_format( $temp, "YYYYMMDD");
  </code></pre>
  
  <p>The code above gives an error:</p>
  
  <blockquote>
    <p><code>date_format()</code> expects parameter 1 to be <code>DateTimeInterface</code></p>
  </blockquote>