date + INTERVAL expr unit date - INTERVAL expr unit mysql> mysql> SELECT '1997-12-31 23:59:59' + INTERVAL 1 SECOND; +-------------------------------------------+ | '1997-12-31 23:59:59' + INTERVAL 1 SECOND | +-------------------------------------------+ | 1998-01-01 00:00:00 | +-------------------------------------------+ 1 row in set (0.00 sec)