adddate(date,INTERVAL expr unit), adddate(expr,days)

當第二個參數INTERVAL形式調用, ADDDATE() 是DATE_ADD() 的同義詞。相關函數SUBDATE() 是 DATE_SUB()的同義詞。有關INTERVAL單位參數信息，請參閱DATE_ADD()的相關討論。

mysql> SELECT DATE_ADD('1998-01-02', INTERVAL 31 DAY);
+---------------------------------------------------------+
| DATE_ADD('1998-01-02', INTERVAL 31 DAY)                 |
+---------------------------------------------------------+
| 1998-02-02                                              |
+---------------------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT ADDDATE('1998-01-02', INTERVAL 31 DAY);
+---------------------------------------------------------+
| ADDDATE('1998-01-02', INTERVAL 31 DAY)                  |
+---------------------------------------------------------+
| 1998-02-02                                              |
+---------------------------------------------------------+
1 row in set (0.00 sec)

當第二個參數的使用天的形式調用，MySQL將其視為被添加天的整數到expr。

mysql> SELECT ADDDATE('1998-01-02', 31);
+---------------------------------------------------------+
| DATE_ADD('1998-01-02', INTERVAL 31 DAY)                 |
+---------------------------------------------------------+
| 1998-02-02                                              |
+---------------------------------------------------------+
1 row in set (0.00 sec)