Mysql 去掉dateTime列，但在可视化/处理数据时，我必须处理每条记录，将UTC更改为本地时区，这需要时间，因此我认为我会保留它。时间戳值不能每年重复一小时，如日期时间。需要时，可以将时间戳转换为本地时间（以说明DST）。我主张去掉任何声明为DATETIME的

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去掉dateTime列，但在可视化/处理数据时，我必须处理每条记录，将UTC更改为本地时区，这需要时间，因此我认为我会保留它。

时间戳

值不能每年重复一小时，如

日期时间

。需要时，可以将

时间戳

转换为本地时间（以说明DST）。我主张去掉任何声明为

DATETIME

的列。

CREATE TABLE `sensordata` (
  `userID` varchar(45) DEFAULT NULL,
  `instrumentID` varchar(10) DEFAULT NULL,
  `utcDateTime` datetime DEFAULT NULL,
  `dateTime` datetime DEFAULT NULL,
  `data` varchar(200) DEFAULT NULL,
  `dataState` varchar(45) NOT NULL DEFAULT 'Original',
  `gps` varchar(45) DEFAULT NULL,
  `location` varchar(45) DEFAULT NULL,
  `speed` varchar(20) NOT NULL DEFAULT '0',
  `unitID` varchar(5) NOT NULL DEFAULT '1',
  `parameterID` varchar(5) NOT NULL DEFAULT '1',
  `originalData` varchar(200) DEFAULT NULL,
  `comments` varchar(45) DEFAULT NULL,
  `channelHashcode` varchar(12) DEFAULT NULL,
  `settingHashcode` varchar(12) DEFAULT NULL,
  `status` varchar(7) DEFAULT 'Offline',
  `id` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id_UNIQUE` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=98772 DEFAULT CHARSET=utf8

Select dateTime from sensordata WHERE userID = 'someUserID' AND instrumentID = 'someInstrumentID' AND dateTime between 'startDate' AND 'endDate' order by dateTime asc;

CREATE TABLE `sensordata` (
  `userID` int,  /* shouldn't this have a foreign key constraint? */
  `instrumentID` int,
  `utcDateTime` datetime DEFAULT NULL,
  `dateTime` datetime DEFAULT NULL,
/* what exactly are you putting here? Are you sure it's not causing any reduncy? */
  `data` varchar(200) DEFAULT NULL, 
 /* your states will be a finite number of elements. They can be represented by constants in your code or a set of values in a related table */
  `dataState` int,
/* what's this? Sounds like what you are saving in location */
  `gps` varchar(45) DEFAULT NULL,
  `location` point,
  `speed` float,
  `unitID` int DEFAULT '1',
/* as above */
  `parameterID` int NOT NULL DEFAULT '1',
/* are you sure this is different from data? */
  `originalData` varchar(200) DEFAULT NULL,
  `comments` varchar(45) DEFAULT NULL,
  `channelHashcode` varchar(12) DEFAULT NULL,
  `settingHashcode` varchar(12) DEFAULT NULL,
/* as above and isn't this the same as */
  `status` int,
  `id` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`),
  UNIQUE KEY `id_UNIQUE` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=98772 DEFAULT CHARSET=utf8

PRIMARY KEY ( userID, instrumentID, utcDateTime)