title: WordPress: show archive even though there are no posts
body: <p>On my WordPress website, I have an archive page e.g.: <code>http://www.example.com/2017</code>. My archive.php file has a query to show <strong>posts</strong> as well as two custom post types: <strong>case-studies</strong> and <strong>media</strong>:</p>
  
  <pre><code>global $wp_query;
          $args = array_merge( $wp_query-&gt;query, array( 'post_type' =&gt; array('post','case-studies','media'), 'posts_per_page' =&gt; 3 ) );
          query_posts( $args );
  
          while ( have_posts() ) : the_post();
  </code></pre>
  
  <p>The archive page will only show provided there are posts under <strong>post</strong> (the standard post type that is included within WordPress) otherwise it will 404, even though there are posts under <strong>case-studies</strong> and <strong>media</strong>. </p>
  
  <p>Is there a workaround this?</p>
  
  <p>Here is a link to my archive.php for those who are interested: <a href="http://s000.tinyupload.com/download.php?file_id=01176873805470321208&amp;t=0117687380547032120854071" rel="nofollow noreferrer">archive.php</a></p>