use GD::Graph::Data;
use GD::Graph::bars;

my $data = GD::Graph::Data->new();

my $sth = $dbh->prepare("SELECT time, mastuntemp, LineTemp, spargtemp FROM brew_temp_tb WHERE sitename = 'Brew' AND batchnumber = '$batchnumber' ORDER BY time";");

if (!$sth->execute()) {
    die "Error: ". $sth->errstr ."\n";
}

my @row;
while (@row = $sth->fetchrow_array) {
    $data->add_point(@row);
}