messages (id, to_user, from_user, created)1 | 1 | 2 | 2009-05-212 | 1 | 3 | 2009-06-213 | 1 | 4 | 2009-07-214 | 2 | 1 | 2009-05-105 | 2 | 3 | 2009-06-106 | 1 | 2 | 2009-07-10
How could I get the most recent message between two users?