Filter ItemRequest SQL to Include Posts with Specific Terms

/**
 * Filter ItemRequest JOIN statement.
 * 
 * @param string $join
 * @param string $post_type                   
 */

add_filter( 'wp_data_sync_item_request_sql_join', function( $join, $post_type ) {

	global $wpdb;

	if ( 'post' === $post_type ) {
		$join .= "
			LEFT JOIN $wpdb->term_relationships tr
			ON tr.object_id = p.ID
			LEFT JOIN $wpdb->term_taxonomy tt
			ON tt.term_taxonomy_id = tr.term_taxonomy_id
			LEFT JOIN $wpdb->terms t
			ON t.term_id = tt.term_id
		";
	}

	return $join;

}, 10, 2 );

/**
 * Filter ItemRequest WHERE statement.
 *
 * @param string $where
 * @param string $post_type
 */

add_filter( 'wp_data_sync_item_request_sql_where', function( $where, $post_type ) {

	global $wpdb;

	if ( 'post' === $post_type ) {
		$where .= "
			AND tt.taxonomy = 'category'
			AND t.slug IN ('news', 'akcii')
		";
	}

	return $where;

}, 10, 2 );