Filter posts by custom fields of the related posts ?

• sdriyaz712

• December 16, 2019 at 8:48 pm

I have two post types named ‘programs’ and ‘universities’, where different programs are connected with different universities.

I want to filter these programs with custom fields of their related universities, such as university’s ranking or location.

I can filter my programs with their own custom fields or taxonomies using WP_Query arguments. However, I want to filter them with their related university’s custom fields.

I went through the complete documentation but couldn’t find a solution.

• sdriyaz712

• December 16, 2019 at 8:57 pm

Here’s what I’ve done so far:

<?php
//filter by custom field
if(isset($_GET['shift']))
	$args['meta_query'][] = array(
		'key' => 'shift',
		'value' => $shift,
		'compare' => 'LIKE'
	);

//filtered by taxonomy
if(isset($terms1))
    $args['tax_query'][] = array(
    	'taxonomy' => 'category',
    	'field' => 'slug',
    	'terms' => $terms1,
    	'operator' => 'IN',

// Don't know how to filter by related post's custom fields

$proSearch_query = new WP_Query($args);
while ($proSearch_query->have_posts()){
	$proSearch_query->the_post();

			$result[] = array(
			"id" => get_the_ID(),
				"title" => get_the_title(),
				"rel_university" => get_field('uni')[0]->post_name,
				//returns related post's custom field:
				"ranking" => get_field('university')[0]->ranking,
			);
}
echo json_encode($result);
die(); 
?>