my $sth = $dbh->prepare("SELECT kunde,umsatz FROM db_kundenumsatz");

my (@kunde, @umsatz,$kunde, $umsatz);

while (($kunde, $umsatz) = $sth->fetchrow_array()){
   push @kunde $kunde;
   push @umsatz, $umsatz;
}
my @data=\@kunde,\@umsatz);
[download]

I think this is what you want, you could of course use anonymous arrays in @data ie push @data->[0] $kunde... However I left it this way for clarity