2014-05-21 03:26:14 | | 7560000001 | 2014-05-20 21:56:42 | 2014-05-21 03:27:45 | | 7650000001 | 2014-05-20 21:56:42 | 2014-05-21 03:28:37 | | 7740000001 | 2014-05-20 21:56:42 | 2014-05-21 03:28:26 | +------------+---------------------+---------------------+ 30 rows in set (0.00 sec)
如果对这种稍微冗余一些的表来进行查询，那么对表的访问以及CPU的资源占用都达到了最低。
mysql> select sec_to_time(avg(timestampdiff(second,start_time,end_time))) as 'Running' from log_ytt_horizontal; +---------------+ | Running | +---------------+ | 05:27:08.8333 | +---------------+ 1 row in set (0.00 sec)