public static function getGroupItemById($id) {
        global $wpdb;

        $csgit = Schema::getComboSetGroupItemsTable();
        $item = $wpdb->get_row(
            $wpdb->prepare("SELECT * FROM {$csgit} WHERE ID = %d", $id),
            ARRAY_A
        );

        if (empty($item)) {
            return null;
        }

        return new GroupItemType(
            $item['ID'],
            $item['group_id'],
            $item['welitem_sku_meta_id'],
            $item['item_label'],
            $item['item_quantity'],
            $item['price_modifier'],
            $item['position'],
            $item['created_at'],
            $item['updated_at']
        );
    }