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我对编写 SQL 查询感到头疼，希望互联网世界的人可以帮助我！

我有一个 mysql 表，其中包含人们何时登录和注销的值，我需要报告一个日期范围的数据，该数据给出一天中每个小时的登录人数。

示例所需的输出：

2013-1-10 00:00 5
2013-1-10 01:00 13
... for every hour of 2013-1-10 ending at 23:00...
2013-1-10 23:00 23
...and then the same for every date in the range...
2013-1-11 00:00 4
2013-1-11 01:00 6

我可以编写查询以按日期对所有内容进行分组，并根据登录时间获取每小时的计数，问题是如果人们登录或超过一个小时，他们的计数将不会在第二个小时出现，因为我' m 按 DATE_FORMAT(time_login, '%H') 分组。

示例查询在这里：

SELECT mac, 
DATE_FORMAT(time_login, '%H') AS hour_logged_in,
DATE_FORMAT(time_logout, '%H') AS hour_logged_out,
DATE_FORMAT(time_login, '%Y-%m-%d') as date,
count(*) as dealcounts 
FROM sessions 
WHERE (
    time_logout IS NOT NULL 
     ) 
AND (
    DATE_FORMAT(time_login, '%Y-%m-%d') BETWEEN 
    DATE_FORMAT('2013-1-1', '%Y-%m-%d') AND DATE_FORMAT('2013-1-18', '%Y-%m-%d')) 
GROUP BY hour_logged_in

有谁知道我如何才能完成每天每小时登录的行数？

我在这里设置了一个 sqlfiddle：http ://www.sqlfiddle.com/#!2/e13a0/7上面的查询

额外学分：没有人登录的小时的空值:-)

很高兴向任何可以提供帮助的人提供一些啤酒和咖啡！！！！谢谢！

4

1 回答 1

1

我认为下面的 mysql 代码与您要找的很接近？

笔记

  1. 它不是优雅的，除非它优雅的方式可以认为一个主要的黑客是优雅的。乍一看可能会因为它的丑陋而引起中度至严重的肠/脑痉挛。

  2. 我的猜测是，它需要添加索引等才能真正使用。

  3. 请注意，我将会话表的名称更改为sessions_example。如果您执行此操作，我不想破坏您的会话表。

  4. 最后，在名为hours_expanded的新表中查找结果。

  5. 它需要更多的测试。我现在累坏了，所以我正在提交潜在的解决方案。我认为一般方法是正确的，代码似乎是正确的，但请验证！

  6. 我通过将登录计数按小时延长到当前时间 (NOW()) 来处理主动登录记录。如果有人可能在没有注销的情况下注销总是进入会话表，那么您可能需要做一些不同的事情。即为标记为活动的记录提出一个最大截止时间。

一般的做法

基本上，当我阅读这个问题时，我知道我的首选方法是将涉及的所有时间“扩展”到实际的表行中。我发现这在这种情况下更适合测试和理解，即使它不一定是一个很好的表现者。当我想办法做到这一点时，我发现了一篇博客文章http://datacharmer.blogspot.com/2007/12/data-from-nothing-solution-to-pop-quiz.html，（参见对 Roland的参考Bouman 和 Kai Voigt）真的，真的帮助我获得了我想要的行扩展。我习惯用 CTE 在 MSSQL 中做这种事情——所以我需要帮助来找到一种在 MySQL 中生成任意数量行的方法。

开始：

/* Following test data from provided sql fiddle */

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;

/*changed name of sessions table to sessions_example, so as not to interfere with any prior sessions table*/
DROP TABLE IF EXISTS sessions_example;
CREATE TABLE `sessions_example` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `network_id` int(11) NOT NULL,
  `mac` varchar(17) NOT NULL,
  `time_login` datetime NOT NULL,
  `time_logout` datetime DEFAULT NULL,
  `data_in` bigint(20) DEFAULT NULL,
  `data_out` bigint(20) DEFAULT NULL,
  `sessionid` varchar(20) NOT NULL,
  `user_ip` varchar(20) DEFAULT NULL,
  `external_ip` varchar(20) DEFAULT NULL,
  `opfield1` varchar(255) DEFAULT NULL,
  `opfield2` varchar(255) DEFAULT NULL,
  `opfield3` varchar(255) DEFAULT NULL,
  `txtfield4` text,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`),
  KEY `sessionid` (`sessionid`),
  KEY `time_login` (`time_login`),
  KEY `time_logout` (`time_logout`),
  KEY `ap_id` (`network_id`),
  KEY `user_id` (`user_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1009253406 ;

INSERT INTO `sessions_example` (`id`, `user_id`, `network_id`, `mac`, `time_login`, `time_logout`, `data_in`, `data_out`, `sessionid`, `user_ip`, `external_ip`, `opfield1`, `opfield2`, `opfield3`, `txtfield4`) VALUES
(1009250911, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 15:45:05', '2013-01-07 16:55:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250912, 0, 254, '00-88-65-D9-B1-8E', '2013-01-07 15:50:04', '2013-01-07 19:11:58', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250914, 0, 254, 'D0-23-DB-17-DC-FA', '2013-01-07 16:20:04', '2013-01-07 17:35:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250915, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 16:25:01', '2013-01-07 16:50:04', NULL, NULL, 'active', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250917, 0, 254, 'E0-B9-BA-F0-45-83', '2013-01-07 16:45:05', '2013-01-07 19:11:58', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250919, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 16:55:05', '2013-01-07 17:12:30', NULL, NULL, 'active', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250920, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 17:12:30', '2013-01-07 17:15:06', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250921, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 17:15:06', '2013-01-07 19:11:59', NULL, NULL, 'active', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250926, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 19:11:59', '2013-01-07 20:30:04', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250927, 0, 254, '00-1B-9E-75-3E-DA', '2013-01-07 19:11:59', '2013-01-07 20:45:04', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250929, 0, 254, '00-88-65-D9-B1-8E', '2013-01-07 20:35:04', '2013-01-07 22:15:04', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250930, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 20:50:04', '2013-01-07 22:25:04', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250931, 0, 254, '00-26-C7-CD-10-9C', '2013-01-07 21:10:04', NULL, NULL, NULL, 'active', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250933, 0, 254, '00-1B-9E-75-3E-DA', '2013-01-07 21:30:04', '2013-01-08 00:20:04', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250934, 0, 254, '00-88-65-D9-B1-8E', '2013-01-07 23:30:04', '2013-01-08 00:05:04', NULL, NULL, 'active', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250935, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-07 23:50:04', '2013-01-08 00:50:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250936, 0, 254, '00-88-65-D9-B1-8E', '2013-01-08 00:05:04', '2013-01-08 02:20:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250940, 0, 254, '00-26-C7-CD-10-9C', '2013-01-08 01:10:05', '2013-01-08 02:10:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250941, 0, 254, '5C-0A-5B-5E-5D-C3', '2013-01-08 01:25:05', '2013-01-08 02:25:06', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250942, 0, 254, '00-88-65-D9-B1-8E', '2013-01-08 03:00:06', '2013-01-08 05:45:07', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009250943, 0, 254, '10-40-F3-6E-D0-FA', '2013-01-08 03:05:07', '2013-01-08 04:45:06', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251100, 0, 254, '28-CF-DA-D9-30-66', '2013-01-08 03:20:06', '2013-01-08 05:10:06', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251101, 0, 253, '00-26-AB-00-E0-1F', '2013-01-08 03:45:03', '2013-01-11 05:15:12', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251102, 0, 253, '8C-A9-82-85-EF-72', '2013-01-08 03:45:03', '2013-01-11 05:25:15', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251103, 0, 253, 'F0-CB-A1-43-A8-4D', '2013-01-08 04:05:03', '2013-01-11 05:15:09', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251104, 0, 254, '00-1B-9E-75-3E-DA', '2013-01-08 04:10:07', '2013-01-08 05:10:07', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251105, 0, 254, 'F8-7B-7A-AC-EA-D6', '2013-01-08 04:20:06', '2013-01-08 06:35:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251106, 0, 253, '90-18-7C-A9-0B-2B', '2013-01-08 04:30:03', '2013-01-11 05:15:14', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251107, 0, 253, '30-F7-C5-C5-9F-61', '2013-01-08 04:30:03', '2013-01-11 05:15:15', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251108, 0, 253, '70-DE-E2-32-F8-66', '2013-01-08 04:30:03', '2013-01-11 09:55:15', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251109, 0, 254, '00-26-C7-CD-10-9C', '2013-01-08 04:55:07', '2013-01-08 06:00:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251110, 0, 254, '5C-0A-5B-A7-54-20', '2013-01-08 05:15:07', '2013-01-08 06:15:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251111, 0, 253, '78-A3-E4-E7-0F-1C', '2013-01-08 05:20:03', '2013-01-11 05:15:06', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251112, 0, 254, '00-1B-9E-75-3E-DA', '2013-01-08 05:35:08', '2013-01-08 06:45:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251113, 0, 253, '00-1F-F3-FA-01-43', '2013-01-08 06:35:04', '2013-01-11 05:15:14', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251114, 0, 253, 'D8-B3-77-7A-C3-F2', '2013-01-08 06:40:03', '2013-01-11 05:15:13', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL),
(1009251128, 0, 254, '00-88-65-D9-B1-8E', '2013-01-08 16:25:08', '2013-01-08 17:40:05', NULL, NULL, 'passive', NULL, NULL, NULL, NULL, NULL, NULL);

/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;

/* end of provided sql fiddle data */

#Here is where we set up a table to hold expansion of all hours in rage as unix timestamp values.
DROP TABLE IF EXISTS hours_expanded;
CREATE TABLE hours_expanded
(
     id int auto_increment,
     hour_as_unix_ts int,
     full_datetime datetime NULL,
     hour_as_time time NULL,
     count_logged_in int DEFAULT 0,
     PRIMARY KEY (id)
);

#get min/max hours
SELECT @min_in := floor(unix_timestamp(min(time_login))/3600), 
    @max_out := floor(unix_timestamp(NOW())/3600)
FROM sessions_example;

#total number of rows that we will need in the `hours_expanded` table

SELECT @hours_in_sessions:= @max_out - @min_in + 1;

#dial up packet length for the string based row-generation solution (see tip of the hat)
SET @old_max_packet = @@max_allowed_packet;
SET GLOBAL max_allowed_packet = 1073741824;

#Next, we will create a long UNION ALL string that will create one row per hour needed.
#For the following concat based approach major tip of the hat to
#http://datacharmer.blogspot.com/2007/12/data-from-nothing-solution-to-pop-quiz.html
#and Roland Bouman who is mentioned there as proposing this solution to generating rows.
SET @one_row_per_hour = (SELECT concat("INSERT INTO hours_expanded (hour_as_unix_ts) ",(repeat(concat(@s:="select 1 ","union all "),@hours_in_sessions)),"select 1;"));

#dial packet length back down
SET GLOBAL max_allowed_packet = @old_max_packet;

#make that a prepared statement via the string and execute
prepare q from @one_row_per_hour;
execute q;

#set hour_as_unix_ts column to actual UNIX TIMESTAMP hour value and full_datetime to show datetime for that hour
UPDATE hours_expanded SET hour_as_unix_ts = (SELECT @min_in * 3600 + 3600 *( id - 1)),
    full_datetime = FROM_UNIXTIME(hour_as_unix_ts),
    hour_as_time = time(full_datetime);

#get the counts and update the hours table
UPDATE hours_expanded h
INNER JOIN
(
    SELECT h.hour_as_unix_ts, COUNT(*) as the_count
    FROM hours_expanded h
    INNER JOIN sessions_example
    WHERE h.hour_as_unix_ts >= floor(unix_timestamp(time_login)/3600)*3600 and h.hour_as_unix_ts <= floor(unix_timestamp(ifnull(time_logout,now()))/3600)* 3600
    GROUP by h.hour_as_unix_ts 
) t on h.hour_as_unix_ts = t.hour_as_unix_ts SET h.count_logged_in = t.the_count;

#null out any hours that have a count of 0
UPDATE hours_expanded SET full_datetime = NULL, hour_as_time = NULL WHERE count_logged_in = 0;

#Final Select with desired output (reformat full_datetime and hour_as_time as desired)
SELECT full_datetime, hour_as_time, count_logged_in FROM hours_expanded WHERE full_datetime IS NOT NULL

关于字符串 concat/repeat 的最后说明。

1000000 行小时，涵盖超过 110 年的时间，需要 13.5M 字符串“SELECT 1 UNION ALL SELECT 1 ...”等。

因此，尽管该方法涉及使用大字符串来获得行扩展，但字符串大小对于所涉及问题的规模来说并不坏——除非你有几千年的会话日志要处理:-}。

我确实将 max_packet_size 临时增加到最大值 (1G)，以确保不会发生任何问题——矫枉过正，具有很大的安全边际。一旦我不再需要它，我就会将 max_packet_size 减小回系统设置。

于 2013-01-20T08:48:37.220 回答