MySQL Tutorial/Date Time Functions/INTERVAL

Date arithmetic also can be performed using INTERVAL together with the + or - operator:

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)

SELECT "1998-01-01" - INTERVAL 1 SECOND;

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

SELECT INTERVAL 1 DAY + "1997-12-31";

mysql>
mysql> SELECT INTERVAL 1 DAY + "1997-12-31";
+-------------------------------+
| INTERVAL 1 DAY + "1997-12-31" |
+-------------------------------+
| 1998-01-01                    |
+-------------------------------+
1 row in set (0.00 sec)
mysql>