Transferring a variable from GET or URL

I want to use the "id" variable from the URL to select that row from the SQL DB...

Right now the only way i know how to do this is by making a new variable for every single option:

if($_GET["id"]=="1")
{ $bbb = '1'; }

if($_GET["id"]=="2")
{ $bbb = '2'; }

if($_GET["id"]=="3")
{ $bbb = '3'; }

Then use the new variable i made to select the row from the DB:

mysql_select_db("vita1_vita");
$query = "select * from vitamins where id = '$bbb'";

Is there any way i can somehow transfer the number directly from the url into the " where id = ""; " so i don't have to list every option?

Thanks for any help!

EDIT:
Wow.. after i thought i tried everything it was really simple 🙂

$bbb = ($_GET["id"]);

That will work, however, you may want to do some validation before you do that ... maybe

if (is_numeric($_GET['id']))
    $bbb = ($_GET["id"]);

Just to keep out the nasties.