Items with Relation macro

items_with_relation.php

<?php

add_action( 'jet-engine/register-macros', function(){ 

    class Items_With_Relation extends \Jet_Engine_Base_Macros {

        public function macros_tag() {
            return 'items_with_relation';
        }

        public function macros_name() {
            return esc_html__( 'Items with Relation', 'jet-engine' );
        }
		
	public function macros_args() {
            return array(
                'rel_id' => array(
					'label'   => __( 'From Relation', 'jet-engine' ),
					'type'    => 'select',
					'options' => function() {
					return jet_engine()->relations->get_relations_for_js( true, __( 'Select...', 'jet-engine' ) );
					},
					'default' => '',
				),
		'rel_object' => array(
					'label'   => __( 'From Object (what to show)', 'jet-engine' ),
					'type'    => 'select',
					'options' => array(
					'parent_object_id' => 'Parents with children',
					'child_object_id'  => 'Children with parents',
					),
					'default' => 'parent_object_id',
				),
            );
        }

        public function macros_callback( $args = array() ) {
			
			$relation_id = $args['rel_id'];
			
			if ( ! $relation_id ) {
				return '';
			}
			
			$relation_object = jet_engine()->relations->get_active_relations( $relation_id );
			
			if ( ! $relation_object ) {
				return '';
			}
			
			$db_table = $relation_object->get_args( 'db_table' );
			
			$object_type = $args['rel_object'];
			
			global $wpdb;
			
			$prefix = $wpdb->prefix;
			
			if ( ! $db_table ) {
				$results = $wpdb->get_results( "SELECT * FROM {$prefix}jet_rel_default AS jet_rel_default  WHERE rel_id = '$relation_id' GROUP BY $object_type;", ARRAY_A );
			} else {
				$results = $wpdb->get_results( "SELECT * FROM {$prefix}jet_rel_$relation_id  WHERE rel_id = '$relation_id' GROUP BY $object_type;", ARRAY_A );
			}
			
			$ids = array_column( $results, $object_type );
			
			return implode( ',', $ids );
        }
    }
    
    new Items_With_Relation();
    
} );