my $querysth = qq{SELECT biblionumber from biblioitems };
$querysth .= " WHERE $wherestring " if ($wherestring);
my $query = $dbh->prepare($querysth);
$query->execute;
while (my $biblionumber = $query->fetchrow){
my $querysth = qq{SELECT biblionumber from biblioitems };
$querysth .= " WHERE $wherestring " if ($wherestring);
my $query = $dbh->prepare($querysth);
$query->execute;
while (my $biblionumber = $query->fetchrow){