$dbh->{RaiseError} = 1; # do this, or check every call for errors
$sth = $dbh->prepare(q{ SELECT region, sales FROM sales_by_region });
$sth->execute;
my ($region, $sales);

# Bind Perl variables to columns:
$rv = $sth->bind_columns(\$region, \$sales);

# you can also use Perl's \(...) syntax (see perlref docs):
#     $sth->bind_columns(\($region, $sales));

# Column binding is the most efficient way to fetch data
while ($sth->fetch) {
    print "$region: $sales\n";
}