PHP Question

I'm trying to database-enable a large web site using PHP/MySQL. Its working out alright, but can't figure my way through one problem:

I'm trying to automate the "Next Page" links to automatically see if there is another page to an article, and if there is, provide a next page link, and if not, give a link back to the Main page. It is sort of working. I'm using a URL in this format:

http://www.mypage.com/test.php?id=1&p=2

So this finds records for article id 1, page 2. But, I don't want to have to say p=1 on all articles. If it is only a one page article, I'd like to be able to leave off the p=1. Do you guys know how to do this?

Right now I'm usaing something like this:

$numpages = mysql_num_rows($content);

if ($numpages > 1) {
printf("%s", mysql_result($content,$p-1,"content"));
$page = mysql_result($content,$p-1,"pagenum");
printf("\n\npage %d", $page);
}
else {
printf("%s", mysql_result($content,0,"content"));
printf(" Back to %s", mysql_result($result,0,"guide"));
}

But, as expected, on a multi-page article, I have to specify p=1 or I get an error. How can I have this pull page 1 without specifying p=1.

As an example, it is similar to anandtech.com . His article system pulls articles based on id #, but all pages after page 1, use the p= variable, while page 1 can be pulled wihtout it in the URL.

I know this is long-winded, but I'd appreciate any help.