Question

我有一个大问题。我需要连接三个表并通过日期列对数据进行排序。我尝试过Sub-Selects，Unions和Joins - 没有成功。

portal_gm_provide是存储全局wms_id的表。
portal_gm_log是存储所有日志记录信息（信息，警告，错误）的表。
portal_gm_cron是存储cronjob信息的表（成功或错误）。

问题是这三个表没有相同的结构，也没有相同的日期字段。我是否可以加入和排序数据，每个适合的数据都在一行中，不需要的字段是NULL，就像在LEFT / RIGHT连接中一样？

SELECT
db_main.wms_id AS id_wms,
db_log.message, db_log.message_real, db_log.id_layer,
db_log.code, db_log.subcode, db_log.counter, db_log.time_first, db_log.time_last,
db_cron.error, db_cron.errorno,
CASE
    WHEN db_log.time_first IS NULL THEN db_cron.time
    ELSE NULL # db_log.time_first
END AS time
FROM portal_gm_provide AS db_main
RIGHT JOIN portal_gm_log AS db_log ON db_log.id_wms = db_main.wms_id
RIGHT JOIN portal_gm_cron AS db_cron ON db_cron.id_wms = db_main.wms_id
WHERE db_main.user_id = 1
ORDER BY time DESC
LIMIT 50

CREATE TABLE IF NOT EXISTS `portal_gm_provide` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `user_id` int(10) unsigned NOT NULL DEFAULT '0',
  `wms_id` int(10) unsigned NOT NULL DEFAULT '0',
  `mail_notify` varchar(100) DEFAULT NULL,
  `mail_period` varchar(100) DEFAULT NULL,
  `time` datetime NOT NULL,
  `time_cron` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `portal_gm_log` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `code` int(10) unsigned NOT NULL DEFAULT '0',
  `subcode` int(10) unsigned DEFAULT '0',
  `id_wms` int(10) unsigned DEFAULT '0',
  `id_layer` int(10) unsigned DEFAULT '0',
  `message` mediumtext,
  `message_real` mediumtext,
  `counter` int(10) unsigned NOT NULL DEFAULT '1',
  `time_first` datetime NOT NULL,
  `time_last` datetime DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `id_wms` (`id_wms`),
  KEY `id_layer` (`id_layer`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `portal_gm_cron` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `id_wms` int(10) unsigned DEFAULT '0',
  `error` varchar(250) DEFAULT NULL,
  `errorno` int(10) unsigned DEFAULT '0',
  `flag` int(10) unsigned DEFAULT '0',
  `time` datetime DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `GM_ID` (`id_wms`),
  KEY `DATUM` (`time`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `portal_gm_provide` (`id`, `user_id`, `wms_id`, `mail_notify`, `mail_period`, `time`, `time_cron`) VALUES
    (1, 1, 2, 'MOD_GEOMONITOR_PROVIDE_NOTIFY_STATE_WARNINGERROR', 'MOD_GEOMONITOR_PROVIDE_NOTIFY_PERIOD_3H', '2011-04-21 10:35:36', '2011-05-13 10:10:02'),
    (2, 1, 1389, 'MOD_GEOMONITOR_PROVIDE_NOTIFY_STATE_WARNINGERRORIN', 'MOD_GEOMONITOR_PROVIDE_NOTIFY_PERIOD_IMMEDIATELY', '2011-05-02 13:42:02', '2011-05-13 11:34:01'),
    (3, 1, 415, 'MOD_GEOMONITOR_PROVIDE_NOTIFY_STATE_WARNINGERRORIN', 'MOD_GEOMONITOR_PROVIDE_NOTIFY_PERIOD_IMMEDIATELY', '2011-05-02 13:42:02', '2011-05-13 11:53:01');

INSERT INTO `portal_gm_log` (`id`, `code`, `subcode`, `id_wms`, `id_layer`, `message`, `message_real`, `counter`, `time_first`, `time_last`) VALUES (578, 8192, 0, 415, 5975, 'Valid SRS not found. Maybe no matching BoundingBox. Defaulting to EPSG:4326.', NULL, 90, '2010-10-21 20:19:42', '2010-10-27 13:42:52');
INSERT INTO `portal_gm_log` (`id`, `code`, `subcode`, `id_wms`, `id_layer`, `message`, `message_real`, `counter`, `time_first`, `time_last`) VALUES (3984, 8192, 0, 415, 5975, 'No valid Box for given SRS not found. Maybe no matching BoundingBox. Defaulting to EPSG:4326.', NULL, 483, '2010-10-27 15:16:05', '2010-12-02 08:18:19');
INSERT INTO `portal_gm_log` (`id`, `code`, `subcode`, `id_wms`, `id_layer`, `message`, `message_real`, `counter`, `time_first`, `time_last`) VALUES (7800, 4352, 0, 415, 0, 'www.umweltkarten.mv-regierung.de', 'every name server provided has failed: Success', 3, '2010-11-26 00:37:05', '2010-11-29 21:34:27');
INSERT INTO `portal_gm_log` (`id`, `code`, `subcode`, `id_wms`, `id_layer`, `message`, `message_real`, `counter`, `time_first`, `time_last`) VALUES (14471, 12288, 0, 1389, 19219, '', NULL, 95, '2011-05-02 14:24:01', '2011-05-13 10:40:51');

INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2530349, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 00:00:27');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2531615, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 02:48:49');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2532882, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 05:36:05');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2534150, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 08:16:10');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2535418, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 11:04:05');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2536684, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 13:56:07');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2537951, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 16:44:20');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2539219, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 19:24:07');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2540489, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-06 21:56:04');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2541758, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 00:40:04');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2543027, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 03:24:01');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2544298, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 06:00:07');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2545566, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 08:48:05');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2546836, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 11:24:19');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2548106, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 14:00:09');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2549374, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 16:44:04');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2550643, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 19:24:01');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2551912, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-07 22:04:02');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2553181, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 00:44:04');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2554451, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 03:20:10');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2555719, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 06:04:05');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2556987, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 08:48:05');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2558256, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 11:28:06');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2559523, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 14:20:04');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2560791, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 17:08:04');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2562060, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 19:48:05');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2563328, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-08 22:28:02');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2564598, 415, 'Error loading XML file. (Not Found, Code: 404)', 256, 5, '2011-05-09 01:04:39');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2531247, 1389, NULL, 0, 5, '2011-05-06 01:36:55');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2532514, 1389, NULL, 0, 5, '2011-05-06 04:24:25');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2533782, 1389, NULL, 0, 5, '2011-05-06 07:04:47');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2535050, 1389, NULL, 0, 5, '2011-05-06 09:48:36');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2536316, 1389, NULL, 0, 5, '2011-05-06 12:44:14');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2537582, 1389, NULL, 0, 5, '2011-05-06 15:36:12');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2538850, 1389, NULL, 0, 5, '2011-05-06 18:16:10');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2541389, 1389, NULL, 0, 5, '2011-05-06 23:28:48');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2542660, 1389, NULL, 0, 5, '2011-05-07 02:04:43');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2543929, 1389, NULL, 0, 5, '2011-05-07 04:48:38');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2545198, 1389, NULL, 0, 5, '2011-05-07 07:32:29');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2546468, 1389, NULL, 0, 5, '2011-05-07 10:12:55');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2547737, 1389, NULL, 0, 5, '2011-05-07 12:52:45');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2549006, 1389, NULL, 0, 5, '2011-05-07 15:32:34');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2550275, 1389, NULL, 0, 5, '2011-05-07 18:08:02');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2551545, 1389, NULL, 0, 5, '2011-05-07 20:48:32');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2552813, 1389, NULL, 0, 5, '2011-05-07 23:32:46');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2554083, 1389, NULL, 0, 5, '2011-05-08 02:08:56');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2555351, 1389, NULL, 0, 5, '2011-05-08 04:52:26');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2556621, 1389, NULL, 0, 5, '2011-05-08 07:28:48');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2557888, 1389, NULL, 0, 5, '2011-05-08 10:16:33');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2559156, 1389, NULL, 0, 5, '2011-05-08 13:00:21');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2560423, 1389, NULL, 0, 5, '2011-05-08 15:52:43');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2561692, 1389, NULL, 0, 5, '2011-05-08 18:36:16');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2562960, 1389, NULL, 0, 5, '2011-05-08 21:16:01');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2564229, 1389, NULL, 0, 5, '2011-05-08 23:56:02');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2565498, 1389, NULL, 0, 5, '2011-05-09 02:32:19');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2566768, 1389, NULL, 0, 5, '2011-05-09 05:08:43');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2568037, 1389, NULL, 0, 5, '2011-05-09 07:48:32');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2569304, 1389, NULL, 0, 5, '2011-05-09 10:40:46');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2570571, 1389, NULL, 0, 5, '2011-05-09 13:28:45');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2571838, 1389, NULL, 0, 5, '2011-05-09 16:16:36');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2573106, 1389, NULL, 0, 5, '2011-05-09 18:56:10');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2574373, 1389, NULL, 0, 5, '2011-05-09 21:40:38');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2575640, 1389, NULL, 0, 5, '2011-05-10 00:24:09');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2576906, 1389, NULL, 0, 5, '2011-05-10 03:16:30');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2578175, 1389, NULL, 0, 5, '2011-05-10 05:52:55');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2579443, 1389, NULL, 0, 5, '2011-05-10 08:32:28');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2580711, 1389, NULL, 0, 5, '2011-05-10 11:20:34');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2581979, 1389, NULL, 0, 5, '2011-05-10 14:00:46');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2583239, 1389, NULL, 0, 5, '2011-05-10 16:32:32');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2584511, 1389, NULL, 0, 5, '2011-05-10 19:04:14');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2585784, 1389, NULL, 0, 5, '2011-05-10 21:29:00');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2587056, 1389, NULL, 0, 5, '2011-05-10 23:56:21');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2589600, 1389, NULL, 0, 5, '2011-05-11 04:56:32');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2590873, 1389, NULL, 0, 5, '2011-05-11 07:20:50');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2592143, 1389, NULL, 0, 5, '2011-05-11 10:00:47');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2593414, 1389, NULL, 0, 5, '2011-05-11 12:36:19');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2594682, 1389, NULL, 0, 5, '2011-05-11 15:28:39');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2595953, 1389, NULL, 0, 5, '2011-05-11 18:04:23');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2597226, 1389, NULL, 0, 5, '2011-05-11 20:28:09');
INSERT INTO `portal_gm_cron` (`id`, `id_wms`, `error`, `errorno`, `flag`, `time`) VALUES (2598498, 1389, NULL, 0, 5, '2011-05-11 22:56:59');

Answer 1

不确定我是否理解你的意思，但我认为你要求将三个表中的每一行显示为一个，使用每个表中的所有列（为其他表中的列添加空值）和排序按日期顺序排列的所有行（最近的第一行）。

使用您的代码作为示例（选择日期列和过滤器），这应该：

SELECT o.*
FROM (
(SELECT id_wms, time AS ordered_time, id, error, errorno, flag, NULL AS code, NULL AS subcode, NULL AS id_layer, NULL AS message, NULL AS message_real, NULL AS counter, NULL AS time_first, NULL AS time_last, NULL AS user_id, NULL AS mail_notify, NULL AS mail_period, NULL AS time_cron
FROM
    portal_gm_cron)
UNION ALL
(SELECT id_wms, time_first AS ordered_time, id, NULL AS error, NULL AS errorno, NULL AS flag, code, subcode, id_layer, message, message_real, counter, time_first, time_last, NULL AS user_id, NULL AS mail_notify, NULL AS mail_period, NULL AS time_cron
FROM
    portal_gm_log)
UNION ALL
(SELECT wms_id as id_wms, time AS ordered_time, id, NULL AS error, NULL AS errorno, NULL AS flag, NULL AS code, NULL AS subcode, NULL AS id_layer, NULL AS message, NULL AS message_real, NULL AS counter, NULL AS time_first, NULL AS time_last, user_id, mail_notify, mail_period, time_cron
FROM
    portal_gm_provide
WHERE
    user_id = 1) 
) AS o
ORDER BY ordered_time DESC

您可以更改列顺序和日期列选择以适应。

MySQL JOIN和ORDER问题（在多个表上排序）

1 个答案: