ACF relationship fields - get_field values from other post type

Question

In my POSTS page (regular post type), I have setup a ACF relationship field. Inside this I can select company name which are all under the post type of directory_listings.

Answer 1

If it's a custom field you are looking for within that query then you can do it like this:

<?php
$posts = get_field('related_articles');

if( $posts ): ?>
    <ul>
    <?php foreach( $posts as $post): // variable must be called $post (IMPORTANT) ?>
        <?php setup_postdata($post); ?>
        <li>
            <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
            <?php the_field('your_custom_field',$post); ?>
        </li>
    <?php endforeach; ?>
    </ul>
    <?php wp_reset_postdata(); // IMPORTANT - reset the $post object so the rest of the page works correctly ?>
<?php endif; ?>

Answer 2

Background Info:

get_field() has three parameters:

1. $field_name: the name of the field to be retrieved. eg "page_content" (required)
2. $post_id: Specific post ID where your value was entered. Defaults to current post ID (not required). This can also be options / taxonomies / users / etc
3. $format_value

If you were only concerned with grabbing a specific post (of which you knew the ID), the key would be the second parameter ($post_id). There's nothing really magical about ACF. Quite simply: the meta_value (i.e. the directory listing the post is tied to) is saved to each post (attached to that post's $post_id).

However, in your case, we don't know the ID of the post(s) we want to get.

Solution:

If we explain what you want to do in a simple sentence, that sentence would look something like:

Show/get posts on a directory_listings (custom post type) page which have a meta_value which points to that page.

Obviously, you can't use get_field(), because your problem has nothing to do with "getting a field." Rather, you need to "find the posts that have a specific field." ACF has great documentation on this.

Luckily for you, WordPress ships with an awesome class called a WP_Query, and a similarly awesome function called get_posts(). So looking back at our sentence above and translating it into a function, we want to: get_posts() where the meta_key has a value of the current $post_id.

Or, more specifically, on your directory_listings page, you'd have the following query:

$related_articles = get_posts(array(
    'post_type' => 'post',
    'meta_query' => array(
        array(
            'key' => 'related_articles', // name of custom field
            'value' => '"' . get_the_ID() . '"',
            'compare' => 'LIKE'
        )
    )
));

if( $related_articles ): 
    foreach( $related_articles as $article ): 

    // Do something to display the articles. Each article is a WP_Post object.
    // Example:

    echo $article->post_title;  // The post title
    echo $article->post_excerpt;  // The excerpt
    echo get_the_post_thumbnail( $article->ID );  // The thumbnail

    endforeach;
endif;

Answer 3

If I understood this correctly this is the same problem than the one I had. In my case I preferred working with shortcodes. Using [acf field="person"] with the field being a relationshipt only gave me the ID of the person, but I was unable to acces their fields. On the other hand, using [acf field="last_name", post_id=[acf field="person"], which would be an ideal solution does not work as the wordpress parser does not allow nested shortcodes.

that is why I cam up with this very small php solution:

function import_cf_from_cpt( $atts ) {
    // import custom fields from other custom post types that are connected via a relationship to the calling custom post type
    // shortcode: [import <field from calling CPT of type relationship> <field name from field from other CPT>]
    // ex [import person last_name] --> Doe

    $postID = do_shortcode("[acf field={$atts[0]}]");
    // we use the first attribute to get the ID of the object
    $postField = get_field($atts[1], $postID);
    // next, using the ID we look for the field of the second attribute.
return $postField;
}
add_shortcode( 'import', 'import_cf_from_cpt' );

Placing this in the functions.php file allows to use the shortcode

[import person last_name] for example, or any other combination to import field values from other posts.