MySQL:DATE_ADD

Question

是否有区别:

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

和

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

Answer 1

不,他们是一样的.

Answer 2

我刚才问了一个类似的问题并自己找到了答案.这是为什么它们是相同的理由:

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)