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

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;