SQLランクと列を変換する簡単な方法

SQLのピボット関数は、列と列の変換に適しているようですが、その複雑さは法外になる可能性があります。これをより簡単に達成したい場合は、次の選択肢を検討してください。

は、すべて、集計関数、およびケースステートメント を使用します。

SELECT name,
  SUM(CASE WHEN color = 'Red' THEN value ELSE 0 END) AS Red,
  SUM(CASE WHEN color = 'Green' THEN value ELSE 0 END) AS Green,
  SUM(CASE WHEN color = 'Blue' THEN value ELSE 0 END) AS Blue
FROM
(
  SELECT color, Paul AS value, 'Paul' AS name
  FROM yourTable
  UNION ALL
  SELECT color, John AS value, 'John' AS name
  FROM yourTable
  UNION ALL
  SELECT color, Tim AS value, 'Tim' AS name
  FROM yourTable
  UNION ALL
  SELECT color, Eric AS value, 'Eric' AS name
  FROM yourTable
) AS src
GROUP BY name

静的解体と視点 ]]

SELECT name, [Red], [Green], [Blue]
FROM
(
  SELECT color, name, value
  FROM yourTable
  UNPIVOT
  (
    value FOR name IN (Paul, John, Tim, Eric)
  ) AS unpiv
) AS src
PIVOT
(
  SUM(value)
  FOR color IN ([Red], [Green], [Blue])
) AS piv

動的視点 ]

DECLARE @colsUnpivot AS NVARCHAR(MAX),
    @query AS NVARCHAR(MAX),
    @colsPivot AS NVARCHAR(MAX)

SELECT @colsUnpivot = STUFF((SELECT ','   QUOTENAME(C.name)
         FROM sys.columns AS C
         WHERE C.object_id = OBJECT_ID('yourtable') AND
               C.name  'color'
         FOR XML PATH('')), 1, 1, '')

SELECT @colsPivot = STUFF((SELECT ','
                         QUOTENAME(color)
                     FROM yourtable AS t
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)')
        , 1, 1, '')

SET @query = 'SELECT name, '   @colsPivot   '
  FROM (
    SELECT color, name, value
    FROM yourtable
    UNPIVOT
    (
      value FOR name IN ('   @colsUnpivot   ')
    ) AS unpiv
  ) AS src
  PIVOT
  (
    SUM(value)
    FOR color IN ('   @colsPivot   ')
  ) AS piv'

EXEC(@query)