mysql> insert into foo (name) VALUES ("foo") on duplicate key update name=name, id=LAST_INSERT_ID(id);
Query OK, 0 rows affected (0.00 sec)

mysql> select LAST_INSERT_ID();
+------------------+
| LAST_INSERT_ID() |
+------------------+
|                1 |
+------------------+
1 row in set (0.00 sec)