Question

我的SQL有点生疏 - 是否有一种SQL方法来投影输入表，如下所示：

Name                SlotValue              Slots
----                ---------              -----
ABC                 3                      1
ABC                 4                      2
ABC                 6                      5

进入“预计”结果表，如下所示：

Name                SlotSum                 Slot
----                -------                 ----
ABC                 13                      1
ABC                 10                      2
ABC                 6                       3
ABC                 6                       4
ABC                 6                       5

换句话说，结果集应该包含等于MAX（Slots）的行数，枚举（Slot）从1到MAX（Slots），并且每个'slot'的Sum应该反映出的总和SlotValues投射到'Slots'位置。对于病理案例：

Name               SlotValue                Slots
----               ---------                -----
ABC                4                        3

我们应该得到：

Name               SlotSum                  Slot
----               -------                  ----
ABC                4                        1
ABC                4                        2
ABC                4                        3

求和逻辑非常简单 - 将每个SlotValue投影到Slots的数量：

SlotValue         SlotValue        SlotValue       Slot             Sum
---------         ---------        ---------       ----             ---
3                 4                6               1                13 (3+4+6)
0                 4                6               2                10 (0+4+6)
0                 0                6               3                6 (0+0+6)
0                 0                6               4                6 (0+0+6)
0                 0                6               5                6 (0+0+6)

更新：最后我在存储过程中使用了LOCALGHOST方法的变体。我希望没有循环可能有办法做到这一点。

Answer 1

我不确定你是否能够在视图中做到这一点。你必须使用一个程序。您也可以在过程中使ProjectedTable成为临时/变量表。我真的很想看看你如何将它变成视图，因为你需要动态生成一系列数字。

declare @maxSlot int 
set @maxSlot = select max(slots) from SlotTable

truncate ProjectedTable
while @i > 0 
    begin
    insert into ProjectedTable (
          SlotSum
          ,Slot
    ) values (
          (select sum(slotValue) from SlotTable where slots >= @maxSlot)
         ,@maxSlot
    )
    set @maxSlot = @maxSlot - 1 
end
select SlotSum, Slot from ProjectedTable

Answer 2

你走了。这将以当前形式执行多达100个插槽。你可以用你的想象力来容纳更多。

DECLARE @SLOT TABLE
    (
    SlotName varchar(25) NOT NULL,
    SlotValue int NOT NULL,
    Slot int NOT NULL
    )

INSERT INTO @SLOT (SlotName, SlotValue, Slot)
    SELECT 'ABC', 3, 1
    UNION
    SELECT 'ABC', 4, 2
    UNION
    SELECT 'ABC', 6, 5

SELECT
    CASE
        WHEN SLOT.SlotName IS NOT NULL THEN SLOT.SlotName
        ELSE 
            COALESCE(
            (SELECT TOP 1 SL.SlotName FROM @SLOT AS SL WHERE SL.Slot < SLOT_PROJECT.Slot ORDER BY SL.Slot DESC),
            (SELECT TOP 1 SL.SlotName FROM @SLOT AS SL WHERE SL.Slot > SLOT_PROJECT.Slot ORDER BY SL.Slot ASC)
            )
    END AS SlotName,
    (
    SELECT
        SUM(SLOT10.SlotValue)
    FROM
        @SLOT AS SLOT10
    WHERE
        SLOT10.Slot >= SLOT_PROJECT.Slot
    ) AS SlotSum,
    SLOT_PROJECT.Slot
FROM
    (
    SELECT
        (TENS.Seq + ONES.Seq) AS Slot
    FROM
        (
        SELECT 1 AS Seq
        UNION ALL
        SELECT 2
        UNION ALL
        SELECT 3
        UNION ALL
        SELECT 4
        UNION ALL
        SELECT 5
        UNION ALL
        SELECT 6
        UNION ALL 
        SELECT 7
        UNION ALL
        SELECT 8
        UNION ALL
        SELECT 9
        ) AS ONES
        CROSS JOIN
        (
        SELECT 0 AS Seq
        UNION ALL
        SELECT 10
        UNION ALL
        SELECT 20
        UNION ALL
        SELECT 30
        UNION ALL
        SELECT 40
        UNION ALL
        SELECT 50
        UNION ALL
        SELECT 60
        UNION ALL 
        SELECT 70
        UNION ALL
        SELECT 80
        UNION ALL
        SELECT 90
        ) AS TENS
    WHERE
        (TENS.Seq + ONES.Seq) <= (SELECT MAX(Slot) FROM @SLOT)
    ) AS SLOT_PROJECT
    LEFT JOIN @SLOT AS SLOT ON
        SLOT.Slot = SLOT_PROJECT.Slot

SQL查询中的投影/复制？

2 个答案: