mysql 5.6中的时间类型的新精度
  在mysql 5.6中,time,timestamp,datetime都可以精确到微妙,并指定微秒的精确度了,
比如如下的例子:
  CREATE TABLE `t` (
  `id` int(11) AUTO_INCREMENT,
  `t1` time(3),
  `t2` timestamp(6),
  `t3` datetime(1),
  `t4` datetime,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB

mysql> select * from t;
+----+--------------+----------------------------+-----------------------+---------------------+
| id | t1           | t2                         | t3                    | t4                  |
+----+--------------+----------------------------+-----------------------+---------------------+
|  1 | 05:05:10.000 | 2013-07-04 05:05:10.000000 | 2013-07-04 05:05:10.0 | 2013-07-04 05:05:10 |
|  2 | 05:14:24.414 | 2013-07-04 05:14:24.125000 | 2013-07-04 05:14:24.4 | 2013-07-04 05:14:25 |
|  3 | 05:14:32.566 | 2013-07-04 05:14:32.207031 | 2013-07-04 05:14:32.3 | 2013-07-04 05:14:32 |
|  4 | 05:14:34.344 | 2013-07-04 05:14:34.507813 | 2013-07-04 05:14:34.5 | 2013-07-04 05:14:35 |
|  5 | 05:14:45.348 | 2013-07-04 05:14:45.832031 | 2013-07-04 05:14:45.1 | 2013-07-04 05:14:45 |


  其中,在http://dev.mysql.com/doc/internals/en/date-and-time-data-type-representation.html中对mysql 5.6中的日期存储位数有了新的解析论述