foreach $key (sort {$a <=> $b} keys %myhash) {
     do stuff;
}

##</code><code>##

$sql = "SELECT record_id, attribute_1, attribute_2 FROM theTable";
$sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr);
$sth->execute() or die("Could not execute!" . $dbh->errstr);

while ($record_id, $att_1, $att_2)  = $sth->fetchrow_array()) {
     $data_hash{$record_id} = {
          att_1 => $att_1,
          att_2 => $att_2
     };
}


$vars = {
     data_hash => \%data_hash
};

$template->process($template_file, $vars)
	|| die "Template process failed: ", $template->error(), "\n";


##</code><code>##

<table class="myClass">
[% FOREACH record_id IN data_hash.keys.sort.reverse %]
     <tr><td>$data_hash.$record_id.att_1</td><td>$data_hash.$record_id.att_2</td></tr>
[% END %]
</table>