SQL Group 和 Pivot 将一对行合并为一行

Question

我在 SQL Server 2016 表中有传感器数据，如下所示：

Created	RealValue	Tag	Units	PairIdentity	PairConfigLabel
2021-11-12 12:00:50.030	67.3519982	temperature	°F	BC72251E-08C0-471A-93A3-C2422C7AB80C	Cutting
2021-11-12 12:00:50.030	53.299999	humidity	%	BC72251E-08C0-471A-93A3-C2422C7AB80C	Cutting
2021-11-12 12:00:50.030	53.25	humidity	%	7D7F8DAC-5BCB-4077-961F-2A985BB6D8CE	Assembly
2021-11-12 12:00:50.030	67.0279982	temperature	°F	7D7F8DAC-5BCB-4077-961F-2A985BB6D8CE	Assembly
2021-11-12 12:00:50.013	36.849998	humidity	%	1A857346-35D2-45FA-80C8-D6523B310026	Laminating
2021-11-12 12:00:50.013	71.564	temperature	°F	1A857346-35D2-45FA-80C8-D6523B310026	Laminating
2021-11-12 12:00:49.997	42.700001	humidity	%	E8FC1476-F082-4C79-889A-5716FCE0A5B8	SLA Lab
2021-11-12 12:00:49.997	72.482	temperature	°F	E8FC1476-F082-4C79-889A-5716FCE0A5B8	SLA Lab
2021-11-12 12:00:49.980	41.049999	humidity	%	D5C651A4-3A4C-429B-88CA-22CBFEDE875D	QC Lab
2021-11-12 12:00:49.980	73.3459982	temperature	°F	D5C651A4-3A4C-429B-88CA-22CBFEDE875D	QC Lab

对于每个温度记录，通常，但不总是有一个相应的湿度读数（可能有湿度行，但没有相应的温度，反之亦然）。它们与PairIdentity 列绑定在一起。我想生成一个查询，该查询将 PairIdentity 上的数据分组并将其透视到一行中，每个分组都包含新列。我不确定我的措辞是否正确，但我正在努力达到与此类似的结果：

Created	Temp	TempUnit	Humidity	HumidityUnit	PairIdentity	PairConfigLabel
2021-11-12 12:00:50.030	67.3519982	°F	53.299999	%	BC72251E-08C0-471A-93A3-C2422C7AB80C	Cutting
2021-11-12 12:00:50.030	67.0279982	°F	53.25	%	7D7F8DAC-5BCB-4077-961F-2A985BB6D8CE	Assembly
2021-11-12 12:00:50.013	71.564	°F	36.849998	%	1A857346-35D2-45FA-80C8-D6523B310026	Laminating

任何提示或帮助将不胜感激。

Answer 1

这只是一个标准的case pivot：

select
    min(Created) as Created,
    min(case when tag = 'temperature' then RealValue end) as Temp,
    min(case when tag = 'temperature' then Units end) as TempUnit,
    min(case when tag = 'humidity' then RealValue end) as Humidity,
    min(case when tag = 'humidity' then Units end) as HumidityUnit,
    PairIdentity,
    min(PairConfigLabel) as PairConfigLabel
from T
group by PairIdentity

Answer 2

从您的示例数据看来，您只需要两个数据集之间的内部连接：

with tmp as (
    select * 
    from t
    where tag='temperature'
), hum as (
    select * 
    from t
    where tag='humidity'
)
select
    t.Created Created, 
    t.RealValue Temp,
    t.Units TempUnit,
    h.RealValue HunidityUnit,
    t.PairIdentity,
    t.PairConfigLabel
from tmp t join hum h on t.PairIdentity=h.PairIdentity;

Answer 3

我不知道我是否非常了解您的数据或结构，或者您想要什么，请在此处发表评论，我很乐意更新或更正我的答案。

主要想法是获得“两张桌子”，一张用于温度，另一张用于湿度，并通过您的PairIdentity 加入它们（如果在两种方法之间是唯一的）。 然后根据联接表的需要显示特定数据。

您可以使用“此连接”和真实数据来获得更高的精度。

    SELECT 
        temp.Created,
        temp.temperature as Temp,
        temp.Units as TempUnit,
        hum.humidity as Humidity,
        hum.Units as HumidityUnit,
        temp.PairIdentity,
        temp.PairConfigLabel
        FROM
        (
        SELECT
        Created,
        RealValue as temperature,
        Units,
        PairIdentity,
        PairConfigLabel
        FROM yourTable
        WHERE Tag = 'temperature'
        ) as temp
        JOIN
        (
        SELECT 
        Created,
        RealValue as humidity,
        Units,
        PairIdentity,
        PairConfigLabel
        FROM yourTable
        WHERE Tag = 'humidity'
        ) as hum
        ON temp.PairIdentity = hum.PairIdentity