my @res = ([qw/DHL K_N Hellmann/]);
while (my @werte = $sth->fetchrow_array()) {
   push @res, [@werte];
}

#!f:/perl/bin/perl

use strict;
use warnings;
use CGI qw(:standard);
use CGI::Carp qw(fatalsToBrowser);
use GD::Graph::pie;
use DBI;
use FindBin;

### Datenbankverbindung ###

my $dbh = DBI->connect("DBI:CSV:f_dir=".$FindBin::Bin.";csv_sep_char=\\;") or die $DBI::errstr;
my $stmt = "SELECT * FROM Kunde";

my $sth = $dbh->prepare($stmt) or die $dbh->errstr();
$sth->execute() or die $dbh->errstr();

my @res = ([qw/DHL K_N Hellmann/]);
while (my @werte = $sth->fetchrow_array()) {
  push @res, [@werte];
}

$sth->finish();
$dbh->disconnect;

### Grafikeigenschaften festlegen ###

my $graph = new GD::Graph::pie(300, 300);

$graph->set(
 title           => 'Auswertung',
 label           => 'Category',
 axislabelclr    => 'black',
 '3d'            => 1,
 start_angle     => 90,
 suppress_angle => 5,
 )
 or die $graph->error;

### Ausgabe ###

my $format = $graph->export_format;
print header("image/$format");
binmode STDOUT;
my $gd = $graph->plot(\@res) or die $graph->error;
print $gd->gif();