mysql - 如何仅使用 mysql 更新日期时间字段的日期？

Question

我有一张这样的 table

| ID |         DATE              | DURATION |     STATUS | DUPLICATION |
|----|------------------- -------|----------|------------|-------------|
|  1 | January, 08 2014 19:30:12 | 00:00:03 |    Aborted |      (null) |
|  2 | January, 08 2014 19:30:12 | 00:00:06 |    Dropped |      (null) |
|  3 | January, 08 2014 05:25:11 | 00:00:20 |  Connected |    Multiple |
|  4 | January, 08 2014 05:19:21 | 00:00:21 |  Connected |      Repeat |
|  5 | January, 08 2014 05:12:56 | 00:00:20 |  Connected |      Unique |
|  6 | January, 08 2014 04:46:56 | 00:00:41 | Unanswered |    Multiple |
|  7 | January, 08 2014 04:42:56 | 00:00:35 | Unanswered |      Repeat |
|  8 | January, 08 2014 04:34:56 | 00:00:31 | Unanswered |      Unique |
|  9 | January, 09 2014 12:06:32 | 00:00:06 |    Dropped |      (null) |
| 10 | January, 09 2014 12:06:32 | 00:00:03 |    Aborted |      (null) |
| 11 | January, 09 2014 05:25:11 | 00:00:20 |  Connected |    Multiple |
| 12 | January, 09 2014 05:19:21 | 00:00:21 |  Connected |      Repeat |
| 13 | January, 09 2014 05:12:56 | 00:00:20 |  Connected |      Unique |
| 14 | January, 09 2014 04:46:56 | 00:00:41 | Unanswered |    Multiple |
| 15 | January, 09 2014 04:42:56 | 00:00:35 | Unanswered |      Repeat |
| 16 | January, 09 2014 04:34:56 | 00:00:31 | Unanswered |      Unique |
| 17 | January, 09 2014 12:19:01 | 00:00:20 |    Aborted |      (null) |
| 18 | January, 09 2014 12:19:01 | 00:00:19 |  Connected |      Repeat |
| 19 | January, 09 2014 12:15:30 | 00:00:20 |    Aborted |      (null) |
| 20 | January, 09 2014 12:15:30 | 00:00:19 |  Connected |      Unique |
| 21 | January, 09 2014 07:25:11 | 00:00:41 |  Connected |    Multiple |
| 22 | January, 09 2014 07:19:21 | 00:00:27 |  Connected |      Repeat |
| 23 | January, 09 2014 07:12:56 | 00:00:20 |  Connected |      Unique |
| 24 | January, 09 2014 06:46:56 | 00:00:32 | Unanswered |      Unique |
| 25 | January, 09 2014 06:42:56 | 00:00:29 |    Aborted |      (null) |
| 26 | January, 09 2014 06:34:56 | 00:00:27 |    Aborted |      (null) |
| 27 | January, 09 2014 05:34:56 | 00:00:27 |    Aborted |      (null) |
| 28 | January, 09 2014 05:25:11 | 00:00:41 |  Connected |    Multiple |
| 29 | January, 09 2014 05:19:21 | 00:00:27 |  Connected |      Repeat |
| 30 | January, 09 2014 05:12:56 | 00:00:20 |  Connected |      Unique |

我只想更新日期，但不知道从哪里开始。我的意思是在日期时间字段 date 中，我想将日期“2014-01-08”更新为“2014-01-01”。我怎样才能做到这一点？这个我试过了。

UPDATE calldate cd
INNER JOIN calldate cdl ON cdl.id = cd.id
SET cd.date = ''/*Dont know what to do here */
WHERE DATE(cd.date) = '2014-01-08'

这是

Fiddle Structure

Answer 1

一个选择是使用这个:

UPDATE `calldata`
SET `date` = DATE_SUB(`date`, INTERVAL 7 DAY)
WHERE DATE(`date`) = '2014-01-08'

fiddle :http://sqlfiddle.com/#!2/28d71/1

为了获得更好的性能，请使用以下查询，因为索引(如果有)可以被 MySQL 使用，因为 DATE() 不在比较运算符的左侧:

UPDATE `calldata`
SET `date` = DATE_SUB(`date`, INTERVAL 7 DAY)
WHERE `date` >= '2014-01-08'
AND `date` < '2014-01-09

fiddle :http://sqlfiddle.com/#!2/7e7b2/1