my $rs = $schema->resultset('Artikel')->search(
    {
        'art2atts.id_at' => $aid,
        def_attgroup => { IN => \@gids }
    },
    {
        select   => ['artnum', 'artname', 'text', ],
        prefetch => ['art2atts'],
        order_by => 'artnum',
    });