$sth->bind_columns( undef, \$orig_service_id, \$orig_stop, $depart_orig);

while ($sth->fetch())
{
    $ids{$orig_service_id} =
    {
        stop_reference => $orig_stop,
        depart_time    => $depart_orig,
    }
}

##</code><code>##

$sth->bind_columns( undef, \$dest_service_id, \$dest_stop, $depart_dest);
while ($sth->fetch())
{
    if (exists ($ids{$dest_service_id})
    {
        print "ID $id exists in both origin and destination set\n";
        print "\t$ids{$dest_service_id}{stop_reference} => $dest_stop\n";
        print "\t$ids{$dest_service_id}{depart_time} => $depart_dest\n";
    }
}