Sorting products by woocommrce attribute value?

Question

WordPress

I've been suffering for some day now ... help me finally figure it out.

dd_filter( 'woocommerce_get_catalog_ordering_args', 'custom_woocommerce_get_catalog_ordering_args' );
function custom_woocommerce_get_catalog_ordering_args( $args ) {
  $orderby_value = isset( $_GET['orderby'] ) ? woocommerce_clean( $_GET['orderby'] ) : apply_filters( 'woocommerce_default_catalog_orderby', get_option( 'woocommerce_default_catalog_orderby' ) );
    if ( 'random_list' == $orderby_value ) {
        $args['orderby'] = array(
             'taxonomy' => 'pa_nominalnaya-moshhnost-kvt',
             'field' => 'slug',
             'terms' => 'pa_nominalnaya-moshhnost-kvt'
         );//поле по которому сортируем
        $args['order'] = 'ASC';//по возрастанию (ASC) или убыванию (DESC)
        $args['meta_key'] = 'pa_nominalnaya-moshhnost-kvt';//по конкретному совпадению ключа
    }
    return $args;
}
add_filter( 'woocommerce_default_catalog_orderby_options', 'custom_woocommerce_catalog_orderby' );
add_filter( 'woocommerce_catalog_orderby', 'custom_woocommerce_catalog_orderby' );
function custom_woocommerce_catalog_orderby( $sortby ) {
    $sortby['random_list'] = 'Сортировка по мощности';
    return $sortby;
}

Answer 1

You have a mess in the arguments, there are both taxonomy and meta_key, and their names are identical. What do you really have, taxonomy or metadata?