如何透视 SQL Server 中的多个列？

Question

将表格“展平”成单行的最佳方法是什么？

例如，使用下表：

+-----+-------+-------------+------------------+
| Id  | hProp | iDayOfMonth | dblTargetPercent |
+-----+-------+-------------+------------------+
| 117 |    10 |           5 |           0.1400 |
| 118 |    10 |          10 |           0.0500 |
| 119 |    10 |          15 |           0.0100 |
| 120 |    10 |          20 |           0.0100 |
+-----+-------+-------------+------------------+

我想生成下表：

+-------+--------------+-------------------+--------------+-------------------+--------------+-------------------+--------------+-------------------+
| hProp | iDateTarget1 | dblPercentTarget1 | iDateTarget2 | dblPercentTarget2 | iDateTarget3 | dblPercentTarget3 | iDateTarget4 | dblPercentTarget4 |
+-------+--------------+-------------------+--------------+-------------------+--------------+-------------------+--------------+-------------------+
|    10 |            5 |              0.14 |           10 |              0.05 |           15 |              0.01 |           20 |              0.01 |
+-------+--------------+-------------------+--------------+-------------------+--------------+-------------------+--------------+-------------------+

我已经设法使用枢轴完成此操作，然后多次重新加入原始表，但我很确定有更好的方法。这按预期工作：

select
X0.hProp,
X0.iDateTarget1,
X1.dblTargetPercent [dblPercentTarget1],
X0.iDateTarget2,
X2.dblTargetPercent [dblPercentTarget2],
X0.iDateTarget3,
X3.dblTargetPercent [dblPercentTarget3],
X0.iDateTarget4,
X4.dblTargetPercent [dblPercentTarget4]
from (
    select
        hProp,
        max([1]) [iDateTarget1],
        max([2]) [iDateTarget2],
        max([3]) [iDateTarget3],
        max([4]) [iDateTarget4]
    from (
        select
            *,
            rank() over (partition by hProp order by iWeek) rank#
        from [Table X]
    ) T
    pivot (max(iWeek) for rank# in ([1],[2],[3], [4])) pv
    group by hProp
) X0
left join [Table X] X1 on X1.hprop = X0.hProp and X1.iWeek = X0.iDateTarget1
left join [Table X] X2 on X2.hprop = X0.hProp and X2.iWeek = X0.iDateTarget2
left join [Table X] X3 on X3.hprop = X0.hProp and X3.iWeek = X0.iDateTarget3
left join [Table X] X4 on X4.hprop = X0.hProp and X4.iWeek = X0.iDateTarget4

Answer 1

这是一种无需进行多重连接即可获得所需结果集的方法。它需要更多的设置并使用两个枢轴操作而不是一个，但避免了多个连接。

我承认我必须查一下，但 Ken O'Bonn 有一篇很棒的文章。 https://blogs.msdn.microsoft.com/kenobonn/2009/03/22/pivot-on-two-or-more-fields-in-sql-server/

/** Build up a Table to work with. **/
DECLARE @T TABLE
    (
    ID INT NOT NULL PRIMARY KEY
    , hProp INT NOT NULL
    , iDayOfMonth INT NOT NULL
    , dblTargetPercent DECIMAL(6,4) NOT NULL
    )

INSERT INTO @T
(ID, hProp, iDayOfMonth, dblTargetPercent)
VALUES (117,10,5,0.1400)
        , (118, 10, 10, 0.0500) 
        , (119, 10, 15, 0.0100)
        , (120, 10, 20, 0.0100)

/** Create a CTE and give us predictable names to work with for
    date and percentage
    **/
;WITH CTE_Rank AS
    (
    SELECT ID
        , hProp
        , iDayOfMonth 
        , dblTargetPercent 
        , sDateName = 'iDateTarget' + CAST(DENSE_RANK() OVER (PARTITION BY hPRop ORDER BY iDayOfMonth) AS VARCHAR(10))
        , sPercentName = 'dblPercentTarget' + CAST(DENSE_RANK() OVER (PARTITION BY hPRop ORDER BY iDayOfMonth) AS VARCHAR(10))
    FROM @T
    )
SELECT hProp 
    , iDateTarget1 = MAX(iDateTarget1)
    , dblPercentTarget1 = MAX(dblPercentTarget1)
    , iDateTarget2 = MAX(iDateTarget2)
    , dblPercentTarget2 = MAX(dblPercentTarget2)
    , iDateTarget3 = MAX(iDateTarget3)
    , dblPercentTarget3 = MAX(dblPercentTarget3)
    , iDateTarget4 = MAX(iDateTarget4)
    , dblPercentTarget4 = MAX(dblPercentTarget4)
FROM CTE_Rank AS R
    PIVOT(MAX(iDayOfMonth) FOR sDateName IN ([iDateTarget1], [iDateTarget2], [iDateTarget3], [iDateTarget4])) AS DayOfMonthName 
    PIVOT(MAX(dblTargetPercent) FOR sPercentName IN (dblPercentTarget1, dblPercentTarget2, dblPercentTarget3, dblPercentTarget4)) AS TargetPercentName
GROUP BY hProp

Answer 2

鉴于：

DECLARE @T table
(
    ID integer NOT NULL PRIMARY KEY,
    hProp integer NOT NULL,
    iDayOfMonth integer NOT NULL,
    dblTargetPercent decimal(6,4) NOT NULL
);

INSERT @T
    (ID, hProp, iDayOfMonth, dblTargetPercent)
VALUES 
    (117, 10, 05, 0.1400),
    (118, 10, 10, 0.0500),
    (119, 10, 15, 0.0100),
    (120, 10, 20, 0.0100);

您可以获得手动数据透视描述的结果：

WITH Ranked AS
(
    SELECT
        T.*,
        rn = ROW_NUMBER() OVER (
            PARTITION BY T.hProp 
            ORDER BY T.iDayOfMonth)
    FROM @T AS T
)
SELECT
    R.hProp,
    iDateTarget1 =      MAX(CASE WHEN R.rn = 1 THEN R.iDayOfMonth END),
    dblPercentTarget1 = MAX(CASE WHEN R.rn = 1 THEN R.dblTargetPercent END),
    iDateTarget2 =      MAX(CASE WHEN R.rn = 2 THEN R.iDayOfMonth END),
    dblPercentTarget1 = MAX(CASE WHEN R.rn = 2 THEN R.dblTargetPercent END),
    iDateTarget3 =      MAX(CASE WHEN R.rn = 3 THEN R.iDayOfMonth END),
    dblPercentTarget3 = MAX(CASE WHEN R.rn = 3 THEN R.dblTargetPercent END),
    iDateTarget4 =      MAX(CASE WHEN R.rn = 4 THEN R.iDayOfMonth END),
    dblPercentTarget4 = MAX(CASE WHEN R.rn = 4 THEN R.dblTargetPercent END)
FROM Ranked AS R
GROUP BY
    R.hProp;

db<>在这里摆弄