How to show a MySQL warning that just happened?

I just ran a simple MySQL CREATE TABLE statement that produced the line >"Query OK, 0 rows affected, 1 warning (0.07 sec)." It didn't actually show me what the warning was, though. How can you see the contents of a warning that just occurred? I'm using MySQL 5.1, if it makes a difference. The only thing I found online was "SHOW WARNINGS;" but that only produced > "Empty set (0.00 sec)."