直接在PDO bindParam中使用POST和GET

In their explanations of PDO, I often see informed writers offer example like these two. The first one uses a simple POST in the bindParam and the second assigns it to a variable first. Before I go about swapping out this old Adobe code for PDO, I'd like to know if one is preferable over the other, i.e. more secure or something else.

 $stmt = $con->prepare("SELECT whatever FROM whatever WHERE AuthorEmail=:id"); 
 $stmt->bindParam(':id', $_POST['AuthorEmail'], PDO::PARAM_STR); 


 $AuthorEmail = $_POST['AuthorEmail'];

 $stmt = $con->prepare("SELECT whatever FROM whatever WHERE AuthorEmail=:id"); 
 $stmt->bindParam(':id', $AuthorEmail, PDO::PARAM_STR);