Posts 2 posts functions for WordPress

how-to-use-posts-2-posts

 <?php
//In functions .php
function my_connection_types() {
p2p_register_connection_type( array(
'name' => 'posts_to_pages',
'from' => 'post',
'to' => 'page'
) );
}
add_action( 'p2p_init', 'my_connection_types' );
?>

<?php
// In Single.php
// Find connected pages
$connected = new WP_Query( array(
  'connected_type' => 'posts_to_pages',
  'connected_items' => get_queried_object(),
  'nopaging' => true,
) );

// Display connected pages
if ( $connected->have_posts() ) :
?>
<h3>Related pages:</h3>
<ul>
<?php while ( $connected->have_posts() ) : $connected->the_post(); ?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php endwhile; ?>
</ul>

<?php 
// Prevent weirdness
wp_reset_postdata();

endif;
?>