sub select_all_biblios {
    my $strsth = qq{ SELECT biblionumber FROM biblioitems };
    $strsth.=qq{ WHERE $where } if ($where);
    $strsth.=qq{ LIMIT $length } if ($length && !$offset);
    $strsth.=qq{ LIMIT $offset,$length } if ($offset);
    my $sth = $dbh->prepare($strsth);
    $sth->execute();
    return $sth;
}