D'oh! My bad, forgot about mysql_error().. I would have gotten there eventually 😉 Thanks tekky!
You are correct; there is no 'booked' collumn in MySQL. What's shows1's structure?
EDIT: Also, if you see the ShowID in the address bar, you are NOT posting ShowID, and need to change $POST['id'] to $GET['id'], though I wouldn't insert raw data from the address bar into a SQL query. Try...
if(!get_magic_quotes_gpc()) $ShowID = addslashes($_GET['id']); else $ShowID = $_GET['id'];
That way you're guarenteed that PHP is stripping quotes so as to prevent from SQL injections.
EDIT2: Code corrected; read next reply.