PDO Prevent duplicate field names?

$sql = "SELECT First, Last, Age, 'Foobar' AS Last;"; This is a simplified example of a SQL query where we're returning two fields with the same name (Last). When I do a fetch_assoc with this query I only get three fields, as the second "Last" field over writes the first one. I was hoping there was some method with PDO that would detect that and throw a warning. Maybe some sort of "strict mode" that would tell me I'm doing something stupid. Is there a way to catch this before it bites me? It already bit me, but moving forward it'd be nice if PHP saw that before I spent an hour debugging it again. - Scott