Mega Code Archive
If you add to or subtract from a date value something that contains a time part, the result is automatically converted
mysql>
mysql> SELECT DATE_ADD('1999-01-01', INTERVAL 1 DAY);
+----------------------------------------+
| DATE_ADD('1999-01-01', INTERVAL 1 DAY) |
+----------------------------------------+
| 1999-01-02 |
+----------------------------------------+
1 row in set (0.00 sec)
mysql>