Fill post query in bricks with meta box relationship posts

When building dynamic WordPress sites with Bricks Builder, there are times when you want to display posts related through a Meta Box relationship field, but also ensure there’s a fallback to show other posts of the same type if no relationships exist. This can be especially helpful for things like testimonials, related articles, or services.

In this post, I’ll walk you through a custom PHP query snippet that does exactly that: it fetches related posts via Meta Box’s relationship field and then fills in the rest of the results with other posts from the same post type — creating a seamless experience for the user and ensuring you never end up with an empty section.

The Goal

We want to:

1. Query posts related to the current post via a Meta Box relationship field.
2. Get all other posts of the same post type.
3. Merge the two, showing related posts first, then fallback posts.

The Code

Here's the full query snippet:

phpCopyEdit$related = new WP_Query([
    'relationship' => [
        'id' => 'review-service',
        'to' => get_the_ID(),
    ],
    'nopaging' => true,
]);

$related_ids = wp_list_pluck($related->posts, 'ID');

$all = new WP_Query([
    'post_type' => 'testimonial',
    'posts_per_page' => -1,
    'fields' => 'ids',
]);

$other_ids = array_diff($all->posts, $related_ids);

return [
    'post_type' => 'testimonial',
    'post__in' => array_merge($related_ids, $other_ids),
    'orderby' => 'post__in',
    'posts_per_page' => -1,
];

Step-by-Step Explanation

1. Query Related Posts via Meta Box Relationship

phpCopyEdit$related = new WP_Query([
    'relationship' => [
        'id' => 'review-service',
        'to' => get_the_ID(),
    ],
    'nopaging' => true,
]);

• This uses Meta Box’s custom relationship query support.
• 'id' => 'review-service' targets your Meta Box relationship field.
• 'to' => get_the_ID() fetches posts connected to the current post.

2. Extract the IDs of Related Posts

phpCopyEdit$related_ids = wp_list_pluck($related->posts, 'ID');

• wp_list_pluck() helps us extract just the post IDs from the $related query.
• We'll use these to prioritize related posts in the final output.

3. Fetch All Testimonials

phpCopyEdit$all = new WP_Query([
    'post_type' => 'testimonial',
    'posts_per_page' => -1,
    'fields' => 'ids',
]);

• This retrieves the IDs of all posts from the testimonial post type.
• 'fields' => 'ids' makes the query more efficient by returning only the IDs.

4. Exclude Already Related Posts

phpCopyEdit$other_ids = array_diff($all->posts, $related_ids);

• We don’t want to show the same post twice.
• array_diff() removes any post already found in the related set.

5. Merge & Return the Final Query

phpCopyEditreturn [
    'post_type' => 'testimonial',
    'post__in' => array_merge($related_ids, $other_ids),
    'orderby' => 'post__in',
    'posts_per_page' => -1,
];

• We merge both arrays — showing related posts first, followed by the rest.
• 'post__in' ensures only these posts are queried and displayed in the order we set.
• 'orderby' => 'post__in' respects the merged array order.

Where to Use This in Bricks Builder

This code goes into a custom query in Bricks Builder:

1. Select your Query Loop element (like a Repeater or Post element).
2. Under the Query panel, choose "Custom PHP".
3. Paste this snippet into the code area.

Make sure your Meta Box relationship field ID (review-service) and post type (testimonial) match your actual site setup.

Resources

• https://docs.metabox.io/extensions/mb-relationships/#get-all-to-objects-for-a-specified-from-object
• https://forum.bricksbuilder.io/t/add-a-meta-query-to-a-query-loop-where-posts-are-filtered-by-metabox-relation/4788/8