RoyK

    my $first = undef;
    my $last = undef;
    my $length = 1;
    while (my ($cid) = $sth2->fetchrow()) {
        if (!defined($first)) {
            $first = $cid;
            next;
        }
        if ($cid == $first+1 or (defined($last) and $cid == $last+1)) {
            $last = $cid;
            $length++;
            next;
        }
        if (!defined($last)) {
            undef($first);
            undef($last);
            $length = 1;
            next;
        }
        if ($cid > $last+1) {
            print "$first\t$last\t$length\n";
            undef($first);
            undef($last);
            $length = 1;
            next;
        }
    }
    print "\n\n";