recover values independently of GET or POST used

I am using some expressions to load the value of a parameter when called, independently if used GET or POST method, using something like: <?php $mydata = (isset($_GET["mydata"])) ? $_GET["mydata"] : (isset($_POST["mydata"])) ? $_POST["mydata"] : 0; echo $mydata; ?> The problem occurs with above code if I call it like: thispage.php?mydata=something , the answer is null (not even '0'). But If I change it to: $mydata = (isset($_POST["mydata"])) ? $_POST["mydata"] : (isset($_GET["mydata"])) ? $_GET["mydata"] : 0; It works, but only with GET method, not post. What is going on? Everytime must be an if/elsif/else routine? What is the origin of the problem? TIA, Joal