Category related -> excerpt, title and thumb in sidebar on article page

I tried using your code and fixing it up but it wasn’t having any luck. Try this out and let me know how it works for you:

<?php
  $args = array( 
    'numberposts' => 3, 
    'order'=> 'DESC', 'orderby' => 'post_date', 
    'category' => '' 
    );
  ?>
<?php
  $postslist = get_posts( $args );
  foreach ($postslist as $post) :  setup_postdata($post);
  ?>
  <h2>
    <a href="https://wordpress.stackexchange.com/questions/36977/<?php the_permalink(); ?>">
    <?php the_title(); ?>
    <?php the_post_thumbnail('thumbnail'); ?></a>
  </h2>
<?php the_excerpt(); ?>
<?php endforeach; ?>