MySQL: DATE_ADD

问题

Is there a difference between:

SELECT DATE_ADD('2005-01-01', INTERVAL 3 MONTH);

and

SELECT '2005-01-01' + INTERVAL 3 MONTH;

回答1:

No, they're the same.

回答2:

I asked a similar question just now and found the answer myself. Here's the justification why they are the same:

SELECT BENCHMARK(20000000, DATE_ADD(NOW(), INTERVAL 3 MONTH));

+--------------------------------------------------------+
| BENCHMARK(20000000, DATE_ADD(NOW(), INTERVAL 3 MONTH)) |
+--------------------------------------------------------+
|                                                      0 |
+--------------------------------------------------------+
1 row in set (1.70 sec)

SELECT BENCHMARK(20000000, NOW() + INTERVAL 3 MONTH);
+-----------------------------------------------+
| BENCHMARK(20000000, NOW() + INTERVAL 3 MONTH) |
+-----------------------------------------------+
|                                             0 |
+-----------------------------------------------+
1 row in set (1.71 sec)

来源：https://stackoverflow.com/questions/1128736/mysql-date-add