Sorting taxonomy columns by meta value numeric

The code I am posting is a modified and simplified version of yours. I got my solution using your code.

/**
 * Filter WP_Term_Query meta query
 *
 * @param   object  $query  WP_Term_Query
 * @return  object
 */
function filter_terms_clauses( $pieces, $taxonomies, $args ) {

    global $pagenow, $wpdb;

    if(!is_admin()) {
        return $pieces;
    }

    if(
        is_admin() 
        && $pagenow == 'edit-tags.php' 
        && $taxonomies[0] == 'typer' 
        && ( isset($_GET['orderby']) && $_GET['orderby'] == 'prioritet' )
    ) {

        $pieces['join']     .= ' INNER JOIN ' . $wpdb->termmeta . ' AS tm ON t.term_id = tm.term_id ';
        $pieces['where']    .= ' AND tm.meta_key = "prioritet"'; 
        $pieces['orderby']   = ' ORDER BY tm.meta_value ';
        $pieces['order']     = isset($_GET['order']) ? $_GET['order'] : "DESC";
    }

    return $pieces;
}

add_filter( 'terms_clauses', 'filter_terms_clauses', 10, 3 );

Hope this one helps.