ACF Taxonomy Field in Query Loop?

How To
1

I am using an ACF Taxonomy field (not a custom taxonomy) that allows the user to select categories from a checkbox list. On the page, I want to loop through each of the selected categories, creating a list of links to each cat archive.

Is there a way to do this with the Query Loop? The ACF Taxonomy field does not show up in the “Type” drop-down the way a Repeater or Relationship field does. I’ve tried to use meta queries, but I don’t have my head wrapped around them well enough to know what I’m doing.

For reference, documentation on the ACF Taxonomy field: https://www.advancedcustomfields.com/resources/taxonomy/

2

A little more information. When I create a code block and use the code below directly from the ACF support page (but with an added var_dump), the field acf_my_taxonomy_field returns null.

<?php 
$terms = get_field('acf_my_taxonomy_field');
echo var_dump($terms); //Added by me, returns NULL
if( $terms ): ?>
    <ul>
    <?php foreach( $terms as $term ): ?>
        <li>
            <h2><?php echo esc_html( $term->name ); ?></h2>
            <p><?php echo esc_html( $term->description ); ?></p>
            <a href="<?php echo esc_url( get_term_link( $term ) ); ?>">View all '<?php echo esc_html( $term->name ); ?>' posts</a>
        </li>
    <?php endforeach; ?>
    </ul>
<?php endif; ?>

However, if I use the dynamic tag {acf_my_taxonomy_field} somewhere else on the page, like in a Basic Text element, it works great and outputs a list of the categories with cat archive links. I can also add :value and it lists the cat ids.

Why can’t I access this custom field via PHP?

3

Ah! I got it to work. This is the code I ended up using for the query, in case anyone else finds this thread and needs it:

$custom_terms = get_field('my_taxonomy_field'); // Access ACF Taxonomy

$custom_terms_string = implode(',', $custom_terms); // Convert to comma separated list

return [
  'taxonomy'   => 'category',
  'orderby'    => 'name',
  'order'      => 'ASC',
  'include'    => $custom_terms_string,
];

So what went wrong before? I’m not positive, but here’s what I found:

  1. I should not have been adding “acf_” to the front of my custom field name in the query editor. Removing that fixed the NULL issue. HOWEVER…
  2. I got some kind of PHP error related to converting strings. Apologies, I’ve lost track of what the exact error was—but this was my cue to convert the field to a plain list of comma separated ids.