SQL 日期分组依据不起作用

Question

我有以下 SQL 代码：

SELECT EXTRACT(MONTH FROM timestamp) AS StatMonth, timestamp
  FROM server_stats
 GROUP BY StatMonth
 ORDER BY StatMonth DESC;

架构：

CREATE TABLE IF NOT EXISTS `server_stats` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `timestamp` int(11) NOT NULL,
  `players_online` bigint(20) NOT NULL,
  `active_players` bigint(20) NOT NULL,
  `total_copper` bigint(20) NOT NULL,
  `total_items` bigint(20) NOT NULL,
  `total_item_weight` bigint(20) NOT NULL,
  `total_houses` bigint(20) NOT NULL,
  `total_boats` bigint(20) NOT NULL,
  `total_pets` bigint(20) NOT NULL,
  `total_experience` bigint(20) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=63 ;

示例数据：

INSERT INTO `server_stats` (`id`, `timestamp`, `players_online`, `active_players`,
        `total_copper`, `total_items`, `total_item_weight`, `total_houses`,
        `total_boats`, `total_pets`, `total_experience`) VALUES
(53, 1317288600, 227, 718, 155037828, 68231283, 25169498, 14822, 2112, 683, 7776385802),
(54, 1317290400, 224, 718, 155038479, 68233576, 25163526, 14822, 2112, 683, 7776669410),
(55, 1317292200, 215, 718, 155100860, 68239613, 25160397, 14822, 2112, 683, 7776933725),
(56, 1317294000, 201, 717, 155095895, 68240842, 25159809, 14822, 2112, 683, 7777196134),
(57, 1317295800, 204, 718, 155090280, 68248539, 25170275, 14822, 2112, 683, 7777419238),
(58, 1317297600, 194, 718, 155105906, 68259213, 25163212, 14823, 2112, 683, 7777657681),
(59, 1317682800, 230, 724, 157323143, 68731571, 25185326, 14908, 2119, 692, 7834358253),
(60, 1317684600, 213, 724, 157323178, 68733325, 25186412, 14908, 2119, 692, 7834637558),
(61, 1317686400, 219, 724, 157314147, 68737824, 25197057, 14908, 2119, 692, 7834904982),
(62, 1317688200, 225, 725, 157329100, 68736384, 25190554, 14909, 2119, 692, 7835169244);

我使用上面的 SELECT 语句来显示每个月。在本例中应该是九月 (9) 和十月 (10)。但是，它仅显示九月，而不显示十月。

有人可以向我解释一下吗？

Answer 1

如果您使用MONTH FROM from_unixtime(timestamp)，这在 MySQL 5.1 中可以正常工作。