MySQL hashes with same key

[jcrush]

# # # # # # # # # # #
#   SQL MAC Query   #
# # # # # # # # # # #
our $smq = $dbh->prepare("select distinct mac,comment from arp.filter 
where operation = 'filter' order by mac") or die "Couldn't prepare 
statement: " . $dbh->errstr;

# # # # # # # # # # # # # # # #
#   SQL Distinct MAC Table    #
# # # # # # # # # # # # # # # #
$smq->execute()
   or die "Couldn't execute statement: " . $smq->errstr;

print "# SQL Distinct MAC HASH #\n";

#   +----------------+-------------------------------------+
#   | mac            | comment                             |
#   +----------------+-------------------------------------+
#   | 1226.b0ab.317e | roving filtered mac                 |
#   | 1226.b0ab.317e | roving filtered mac [force filter   |
#   | 1226.b0ab.317e | [thor2] Excessive Campus Bandwidth  |
#   +----------------+-------------------------------------+
#   3 rows in set (0.04 sec)

our $mac_t = "1226.b0ab.317e"; 

my $ref = $dbh->selectall_hashref("select distinct mac,comment from 
arp.filter where  operation = 'filter' order by mac", 'mac');

foreach my $id (keys %$ref)
{
 if ($mac_t eq $ref->{$id}{mac})
 {
   print "Found a row: mac = $ref->{$id}{mac}, 
comment = $ref->{$id}{comment}\n";
 }
}

The results printed are missing all 3 rows of data

# SQL Distinct MAC HASH #
Found a row: mac = 1226.b0ab.317e, comment = [thor2] Excessive . . .
# END SQL Distinct MAC HASH #

Am I forced to use Arrays, and if so how is the best way to do that?
If using an Array
What happens if I want search one address, and print out all comments attached to that one mac address? (Reason for my hash usage)
For example, if I have 100 macs, and if one is in the database, then print out all the comments on that mac. Thank You, very much for the help Perl Monks !