Question

我已经得到一个地球科学数据数据库，其任务是查询样品位置以及几种元素（金砷，铅和铜）的分析结果。在以前的数据库中，我处理的分析结果已列在表中，其中每个标头是一个元素，主键是样品ID。

此政府数据库已在列中列出了元素

(dbo.SurfaceSampleAttr.AttributeColumn)，其结果在第二列(dbo.SurfaceSampleAttr.AttributeValue)中。我设法能够使用以下代码查询一个元素。

SELECT
    dbo.SurfaceSample.SampleId, 
    dbo.SurfaceSample.CompanySampleId,
    dbo.SurfaceSampleCoordinate.Easting,
    dbo.SurfaceSampleCoordinate.Northing,
    dbo.SurfaceSampleCoordinate.Datum,
    dbo.SurfaceSampleCoordinate.Projection,
    dbo.SurfaceSampleCoordinate.Zone,
    dbo.SurfaceSample.CompanyId,
    dbo.SurfaceSample.SurfaceSampleType,
    dbo.MRTHeader.HeaderValue AS 'Tenement Holder',
    dbo.SurfaceSampleAttr.AttributeValue
FROM
    ((dbo.SurfaceSample
INNER JOIN 
    dbo.SurfaceSampleCoordinate ON dbo.SurfaceSample.Id = dbo.SurfaceSampleCoordinate.SurfaceSampleId)
LEFT JOIN 
    dbo.SurfaceSampleAttr ON dbo.SurfaceSampleCoordinate.SurfaceSampleId = dbo.SurfaceSampleAttr.SurfaceSampleId
                          AND ((dbo.SurfaceSampleAttr.AttributeColumn) = 'Au_ppb'))
INNER JOIN 
    dbo.MRTHeader ON dbo.SurfaceSample.CompanyId = dbo.MRTHeader.MRTFileId
WHERE
    (((dbo.SurfaceSampleCoordinate.Zone) = '50')
    AND ((dbo.MRTHeader.HeaderNumber) = 'H0101'));

我理想的最终状态是列出所有样本位置元数据，例如样本ID，位置，公司等，然后将分析左移并带别名加入右侧”；并非所有样本都具有全部（或任何）分析结果，因此我不想将其过滤掉。

我已经尝试在整个FROM中添加其他带括号的SELECT条件，以及尝试在上述代码中添加其他JOIN，但是我无法弄清楚如何为同一列提供具有不同条件的不同别名。

编辑：

如果语法正确，我想以这种方式工作：

SELECT
    dbo.SurfaceSample.SampleId,
    dbo.SurfaceSample.CompanySampleId,
    dbo.SurfaceSampleCoordinate.Easting,
    dbo.SurfaceSampleCoordinate.Northing,
    dbo.SurfaceSampleCoordinate.Datum,
    dbo.SurfaceSampleCoordinate.Projection,
    dbo.SurfaceSampleCoordinate.Zone,
    dbo.SurfaceSample.Anumber,
    dbo.SurfaceSample.CompanyId,
    dbo.SurfaceSample.SurfaceSampleType,
    dbo.MRTHeader.HeaderValue AS 'Tenement Holder',
FROM
    (dbo.SurfaceSample
LEFT JOIN 
    (SELECT
         dbo.SurfaceSampleAttr.AttributeValue AS 'Au_ppb'
     FROM
         dbo.SurfaceSampleAttr
     WHERE
         (dbo.SurfaceSampleAttr.AttributeColumn) = 'Au_ppb') ON dbo.SurfaceSampleCoordinate.SurfaceSampleId = dbo.SurfaceSampleAttr.SurfaceSampleId
LEFT JOIN 
    (SELECT
         dbo.SurfaceSampleAttr.AttributeValue AS 'Cu_ppm'
     FROM
         dbo.SurfaceSampleAttr
     WHERE
         (dbo.SurfaceSampleAttr.AttributeColumn) = 'Cu_ppm') ON dbo.SurfaceSampleCoordinate.SurfaceSampleId = dbo.SurfaceSampleAttr.SurfaceSampleId
LEFT JOIN 
    (SELECT
         dbo.SurfaceSampleAttr.AttributeValue AS 'Ars_ppm'
     FROM
         dbo.SurfaceSampleAttr
     WHERE
         (dbo.SurfaceSampleAttr.AttributeColumn) = 'Ars_ppm') ON dbo.SurfaceSampleCoordinate.SurfaceSampleId = dbo.SurfaceSampleAttr.SurfaceSampleId
LEFT JOIN 
    (SELECT
         dbo.SurfaceSampleAttr.AttributeValue AS 'Pb_ppm'
     FROM
         dbo.SurfaceSampleAttr
     WHERE
         (dbo.SurfaceSampleAttr.AttributeColumn) = 'Pb_ppm') ON dbo.SurfaceSampleCoordinate.SurfaceSampleId = dbo.SurfaceSampleAttr.SurfaceSampleId)
WHERE
    (((dbo.SurfaceSampleCoordinate.Zone) = '50')
    AND ((dbo.MRTHeader.HeaderNumber) = 'H0101'));

上面的屏幕截图是dbo.SurfaceSampleAttr表，而我感兴趣的两列是.AttributeColumn和.AttributeValue。他们没有将元素作为标题，而是将它们列在一栏中。

编辑 Tried the pivot approach. A step closer, but there are a lot of Null values

Answer 1

尝试在旋转之前预先选择列：

SELECT p.*
FROM (
    SELECT
        dbo.SurfaceSampleAttr.SampleId,
        dbo.SurfaceSampleAttr.AttributeColumn,
        dbo.SurfaceSampleAttr.AttributeValue
    FROM dbo.SurfaceSampleAttr
) t
PIVOT (
   Min(AttributeValue)
   FOR AttributeColumn IN ([Au_ppb], etc)
) p

此外，如果您将MS Access用作前端，则它提供了更灵活，功能更强大的TRANSFORM ... PIVOT ...查询，该查询明确允许在旋转时按多个列进行分组，并动态确定列名。

SQL-从一列中选择不同的（4）值，并显示为四个独立的列

1 个答案: