Query categories from a custom posttype?

Hello, that should help. “types” are category(ie taxonomy) within your custom postype. “references” is the custom post type in my code

<?php
        $terms = get_terms("types");
        $count = count($terms);
 	if ( $count > 0 ){
 	  foreach ( $terms as $term ) {
	  echo "<h2>" . $term->name . "</h2>";
	  $args = array(
               'numberposts' => 1,
               'orderby' => 'post_date',
    	       'order'           => 'DESC',
   	       'post_type' => 'references',
   	       'types' => $term->slug,
   	       'post_status' => 'publish'
	   );
           $sommaire_cat = get_posts ( $args );
	   foreach( $sommaire_cat as $post ) : ?>
           <a href="<?php the_permalink(); ?>"><?php the_title();?></a>
	   <?php endforeach;
		 }

 	 }
?>