使用SQL Server PIVOTing數據

Question

好的，當我什至不知道如何開槍時，我都望而卻步。 我根據Technet基本文章（ http://technet.microsoft.com/zh-cn/library/ms177410(v=sql.105).aspx ）編寫了此SQL。

Select LogTime, Location, LA95Day, LA95Evening, LA95DEn, LA95Night from 
(Select LogTime, Location, LAValue, ValueType  from Project_5_CalculatedData 
     where ValueType in ('LA95Day','LA95Evening','LA95DEn','LA95Night')  )  as c
PIVOT(
Max(LAValue) For ValueType in (LA95Day,LA95Evening,LA95DEn,LA95Night)) as PVt

我的表結構類似於

DataID  Location    LogTime LAValue ValueType
10117   Meter1  2012-09-25 00:00:00.000 71.12   LA95Day
10118   Meter1  2012-09-25 00:00:00.000 55.52   LA95Evening
10119   Meter1  2012-09-25 00:00:00.000 52.69   LA95Night
10120   Meter1  2012-09-25 00:00:00.000 68.62   LA95Den
10121   Meter1  2012-09-26 00:00:00.000 72.21   LA95Day
10122   Meter1  2012-09-26 00:00:00.000 54.10   LA95Evening
10123   Meter1  2012-09-26 00:00:00.000 48.30   LA95Night
10124   Meter1  2012-09-26 00:00:00.000 69.38   LA95Den

編輯 ：這里的數據不完整..我們有4000行..因此，您可以假設MEter2，Meter3，Meter4的位置將與示例數據中的日期相同或不同。 **編輯結束**

我們最多可以記錄4米，數據ID並不重要。 但是我希望所有儀表數據都對齊，我編寫的上述查詢確實部分起作用，即它顯示數據為：

LogTime Location    LA95Day LA95Evening LA95DEn LA95Night
2012-09-25 00:00:00.000 Meter1  71.12   55.52   68.62   52.69
2012-09-26 00:00:00.000 Meter1  72.21   54.10   69.38   48.30
2012-09-27 00:00:00.000 Meter1  68.88   47.77   66.05   46.02
2012-09-28 00:00:00.000 Meter1  73.52   49.23   70.56   43.60
2012-09-29 00:00:00.000 Meter1  54.09   44.87   52.85   41.64
2012-09-30 00:00:00.000 Meter1  51.46   48.61   51.94   41.60
2012-10-01 00:00:00.000 Meter1  73.09   51.78   70.17   46.20

但是我要根據使用的表計； LAday，晚上，Den和晚上最多重復4次； 應用中每米使用一次。 即欲望輸出[列]需要是

LogTime M1-LA95Day  M1-LA95Evening  M1-LA95DEn  M1-LA95Night M2-LA95Day M2-LA95Evening  M2-LA95DEn  M2-LA95Night M3-LA95Day M3-LA95Evening  M3-LA95DEn  M3-LA95Night M4-LA95Day M4-LA95Evening  M4-LA95DEn  M4-LA95Night

哦，我正在嘗試嘗試，因為我以前從未使用過Pivot，甚至不知道我上面的查詢是如何工作的，如果您能解釋一下該查詢將幫助我進行下一步的話。 謝謝。

Answer 1

在我看來，您正在嘗試將所有儀表及其valueTypes列為列。 如果是這種情況，那么您應該可以使用以下內容：

Select LogTime, 
    Meter1_LA95Day, Meter1_LA95Evening, Meter1_LA95DEn, Meter1_LA95Night,
    Meter2_LA95Day, Meter2_LA95Evening, Meter2_LA95DEn, Meter2_LA95Night,
    Meter3_LA95Day, Meter3_LA95Evening, Meter3_LA95DEn, Meter3_LA95Night,
    Meter4_LA95Day, Meter4_LA95Evening, Meter4_LA95DEn, Meter4_LA95Night 
from 
(
    Select LogTime, 
        ValueType = Location+'_'+ValueType,
        LAValue       
    from Project_5_CalculatedData 
    where ValueType in ('LA95Day','LA95Evening','LA95DEn','LA95Night')  
)  as c
PIVOT
(
    Max(LAValue) 
    For ValueType in (Meter1_LA95Day, Meter1_LA95Evening, Meter1_LA95DEn, Meter1_LA95Night,
                      Meter2_LA95Day, Meter2_LA95Evening, Meter2_LA95DEn, Meter2_LA95Night,
                      Meter3_LA95Day, Meter3_LA95Evening, Meter3_LA95DEn, Meter3_LA95Night,
                      Meter4_LA95Day, Meter4_LA95Evening, Meter4_LA95DEn, Meter4_LA95Night)
) as PVt;

請注意，這假設儀表實際上被命名為meter1 ， meter2等等。如果您的儀表沒有被稱為meter1等等，並且它們的名稱可能不相同，那么您可能想要使用動態SQL來獲得結果：

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(Location+'_'+ValueType) 
                    from Project_5_CalculatedData
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT LogTime,' + @cols + ' 
            from 
            (
                Select LogTime, 
                    ValueType = Location+''_''+ValueType,
                    LAValue       
                from Project_5_CalculatedData 
                where ValueType in (''LA95Day'',''LA95Evening'',''LA95DEn'',''LA95Night'')  
            ) x
            pivot 
            (
                max(LAValue)
                for ValueType in (' + @cols + ')
            ) p '

execute sp_executesql @query;

這些將產生結果：

+-------------------------+----------------+----------------+--------------------+------------------+----------------+----------------+--------------------+------------------+----------------+----------------+--------------------+------------------+
|         LogTime         | Meter1_LA95Day | Meter1_LA95Den | Meter1_LA95Evening | Meter1_LA95Night | Meter2_LA95Day | Meter2_LA95Den | Meter2_LA95Evening | Meter2_LA95Night | Meter3_LA95Day | Meter3_LA95Den | Meter3_LA95Evening | Meter3_LA95Night |
+-------------------------+----------------+----------------+--------------------+------------------+----------------+----------------+--------------------+------------------+----------------+----------------+--------------------+------------------+
| 2012-09-25 00:00:00.000 | 71.12          | 68.62          | 55.52              | 52.69            | 71.12          | 68.62          | 55.52              | 52.69            | NULL           | NULL           | NULL               | NULL             |
| 2012-09-26 00:00:00.000 | 72.21          | 69.38          | 54.10              | 48.30            | NULL           | NULL           | NULL               | NULL             | 72.21          | 69.38          | 54.10              | 48.30            |
+-------------------------+----------------+----------------+--------------------+------------------+----------------+----------------+--------------------+------------------+----------------+----------------+--------------------+------------------+