my $sth = $dbh->prepare("SELECT item1 as _first_item, item2 as _second_item, item3 as _third_item FROM table WHERE topic = ? ORDER BY id ASC");
  my @loop = map {
    $sth->execute( $_ );
    {  _TOPIC => $_,  _ITEMS => $sth->fetchall_arrayref({})  };
  } @topic[0 .. $x-1];