Populate a Relationship field with a Repeater on the same post

• DACrosby, LLC

• August 8, 2014 at 9:22 am

I have a Repeater field of Post Objects (here, a custom post type Participants) and I’d like a Relationship field’s options to be populated based on the Post Objects that were selected. I created a stand-alone function with an SQL query which works perfectly using $wpdb->get_results(), but I can’t figure out how to convert it into the WP_Query required by a Relationship field, or if there’s a way to simply feed the Relationship field the options I need directly.

Here’s the SQL that correctly gets my required data directly:

function get_class_participants($class_id){
	global $wpdb;
	$results = $wpdb->get_results(
		"SELECT *
		FROM  <code>wp_postmeta</code> m
		JOIN wp_posts part	ON part.ID = m.meta_value
		WHERE part.ID		= m.meta_value
			AND m.meta_key	LIKE 'participants_%_participant'
			AND m.post_id	= '$class_id'
			AND post_type	= 'participant'
			AND post_status	= 'publish'
	")  or die(mysql_error());
	return $results;
}

And here’s what I have so far using the acf/query filter (It doesn’t work):

	add_filter( 'acf/fields/relationship/query/key=field_53d35e7b7908b', 'acf_participation_participants_meta_query');
function acf_participation_participants_meta_query( $args, $field, $post ) {
	$args['meta_query'] = array(
		array(
			'key' => 'participants_%_participant',
			'value' => '<code>wp_posts</code>.<code>ID</code>',
			'compare' => '='
		)
	);
	return $args;
}

This was also needed to get the post_query to search LIKE meta_key.

add_filter( 'posts_where', 'acf_repeater_dynamic_where', 10, 2 );
function acf_repeater_dynamic_where( $where, &$wp_query ){
	if( !empty( $wp_query->meta_query->queries ) ){
		$keys = wp_list_pluck( $wp_query->meta_query->queries, "key" );
		foreach( $keys as $key ){
			if( strpos( $key, '%') !== false ){
				// custom filter to replace '=' with 'LIKE' for key
				$where = str_replace("meta_key = '{$key}'", "meta_key LIKE '{$key}'", $where);
			}
		}
	}
	return $where;
}