MySql行到列（但動態行）

Question

這是我的SQL表和數據。 http://sqlfiddle.com/#!9/effe2

CREATE TABLE IF NOT EXISTS `CustomValue` (
  `id` int(11) NOT NULL,
  `customFieldId` int(11) NOT NULL,
  `relatedId` int(11) NOT NULL,
  `fieldValue` text COLLATE utf8_unicode_ci,
  `createdAt` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
) ENGINE=MyISAM AUTO_INCREMENT=8 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

INSERT INTO `CustomValue` (`id`, `customFieldId`, `relatedId`, `fieldValue`, `createdAt`) VALUES
(1, 10, 4031, NULL, '2015-11-05 04:25:00'),
(2, 14, 4031, 'adsas@das.sadsa', '2015-11-05 04:25:00'),
(3, 13, 4031, '456', '2015-11-05 04:25:00'),
(4, 16, 4031, '2015-11-09', '2015-11-05 04:25:00'),
(5, 9, 4031, '456', '2015-11-05 04:25:00'),
(6, 11, 4031, 'dsasda', '2015-11-05 04:25:00'),
(7, 15, 4031, '1', '2015-11-05 04:25:00');

現在是這樣，

id  customFieldId   relatedId   fieldValue         createdAt
1   10                 4031     (null)             November, 05 2015 04:25:00
2   14                 4031     adsas@das.sadsa    November, 05 2015 04:25:00
3   13                 4031     456                November, 05 2015 04:25:00
4   16                 4031     2015-11-09         November, 05 2015 04:25:00
5   9                  4031     456                November, 05 2015 04:25:00
6   11                 4031     dsasda             November, 05 2015 04:25:00
7   15                 4031     1                  November, 05 2015 04:25:00

我需要按relatedId分組，並為每個relatedId獲取最終輸出為1行。

這是參考表。

CREATE TABLE IF NOT EXISTS `CustomField` (
  `id` int(11) NOT NULL,
  `customTypeId` int(11) NOT NULL,
  `fieldName` varchar(64) COLLATE utf8_unicode_ci DEFAULT NULL,
  `relatedTable` varchar(64) COLLATE utf8_unicode_ci DEFAULT NULL,
  `defaultValue` text COLLATE utf8_unicode_ci,
  `sortOrder` int(11) NOT NULL DEFAULT '0',
  `enabled` char(1) COLLATE utf8_unicode_ci DEFAULT '1',
  `listItemTag` char(1) COLLATE utf8_unicode_ci DEFAULT NULL,
  `required` char(1) COLLATE utf8_unicode_ci DEFAULT '0',
  `onCreate` char(1) COLLATE utf8_unicode_ci DEFAULT '1',
  `onEdit` char(1) COLLATE utf8_unicode_ci DEFAULT '1',
  `onView` char(1) COLLATE utf8_unicode_ci DEFAULT '1',
  `listValues` text COLLATE utf8_unicode_ci,
  `label` varchar(64) COLLATE utf8_unicode_ci DEFAULT NULL,
  `htmlOptions` text COLLATE utf8_unicode_ci
) ENGINE=MyISAM AUTO_INCREMENT=17 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

INSERT INTO `CustomField` (`id`, `customTypeId`, `fieldName`, `relatedTable`, `defaultValue`, `sortOrder`, `enabled`, `listItemTag`, `required`, `onCreate`, `onEdit`, `onView`, `listValues`, `label`, `htmlOptions`) VALUES
(13, 1, 'HOMEEMAIL', 'people', '', 0, '1', NULL, '1', '1', '1', '1', NULL, 'Home Email', ''),
(9, 1, 'LANDPHONENO', 'people', '', 0, '1', NULL, '1', '1', '1', '1', NULL, 'Land Phone No', ''),
(10, 12, 'ABOUTME', 'people', '', 0, '1', NULL, '0', '1', '1', '1', NULL, 'About Me', ''),
(11, 3, 'PHONENUMBER2', 'people', '', 0, '1', NULL, '1', '1', '1', '1', NULL, 'Phone Number 2', ''),
(14, 3, 'ALTERNATEEMAIL', 'people', '', 0, '1', NULL, '1', '1', '1', '1', NULL, 'Alternate Email', ''),
(15, 11, 'SCHOOLING?', 'people', '', 0, '1', NULL, '1', '1', '1', '1', NULL, 'Schooling?', ''),
(16, 4, 'JOINDATE', 'people', '', 0, '1', NULL, '1', '1', '1', '1', NULL, 'Join Date', '');

最終輸出應為

relatedId | Alternate Email | Home Email | Join Date | Land Phone No | Phone Number 2 | Schooling?
--------------------------------------------------------------------------------------------------
4031      | adsas@das.sadsa | 456        | 2015-11-09| 456           | dsasda         | 1

relatedId | Alternate Email | Home Email | Join Date | Land Phone No | Phone Number 2 | Schooling? | Interest
--------------------------------------------------------------------------------------------------
4033      | adsas@das.sadsa | 456        | 2015-11-09| 456           | dsasda         | 1 | Drawing

phpmyadmin的輸出

Answer 1

這里需要的是將PIVOT行分成列，但是MySQL沒有像SQL Server或Oracle這樣的本地透視運算符。 但是，您可以將CASE表達式與group by一起使用，例如：

SELECT 
  v.relatedId, v.CreatedAt,
  MAX(IF(f.fieldName = 'ABOUTME', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'ABOUTME',
  MAX(IF(f.fieldName = 'ALTERNATEEMAIL', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'ALTERNATEEMAIL',
  MAX(IF(f.fieldName = 'HOMEEMAIL', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'HOMEEMAIL',
  MAX(IF(f.fieldName = 'JOINDATE', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'JOINDATE',
  MAX(IF(f.fieldName = 'LANDPHONENO', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'LANDPHONENO',
  MAX(IF(f.fieldName = 'PHONENUMBER2', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'PHONENUMBER2',
  MAX(IF(f.fieldName = 'SCHOOLING?', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS 'SCHOOLING?'
FROM customField AS f
INNER JOIN Customvalue AS v ON f.Id = v.customFieldId 
GROUP BY   v.relatedId, v.CreatedAt;

要動態地執行此操作，您必須使用動態sql來執行此操作，如下所示：

SET @Colvalues = NULL;
SET @sql = NULL;

SELECT
  GROUP_CONCAT(DISTINCT CONCAT('MAX(IF(f.fieldName = ''',
      f.fieldName, ''', COALESCE(v.fieldValue, f.defaultValue) , NULL)) AS ', '''', f.fieldName , '''')
  ) INTO @Colvalues
FROM customField AS f
INNER JOIN Customvalue AS v ON f.Id = v.customFieldId;


SET @sql = CONCAT('SELECT 
    v.relatedId, v.CreatedAt, ', @Colvalues , '
FROM customField AS f
INNER JOIN Customvalue AS v ON f.Id = v.customFieldId 
GROUP BY   v.relatedId, v.CreatedAt;');

PREPARE stmt 
FROM @sql;

EXECUTE stmt;

注意：

• 如果該字段值為null，它將從默認值字段設置該值，這就是COALESCE(v.fieldValue, f.defaultValue)作用。
• 您可以通過添加WHERE v.fieldValue IS NOT NULL來消除NULL值，例如在Aboutname情況下。

這將為您提供：