sql - 使用 MS Access 数据库的尾随十二个月公式

Question

我有一个名为的数据库Cash_Flow_Statements，我需要创建一个已保存的查询来计算过去十二个月 (TTM) 的自由现金流。

这是我的数据库的示例：

这是我保存的查询的代码。我已将此代码用于其他计算，所以我知道它有效。我只是不知道如何在 SQL 中执行尾随十二个月。

CREATE PROC " & Calculation & " AS _
SELECT Income_Statements.Ticker, Income_Statements.[Year], Income_Statements.Period, _
" & Formula & " AS TTM _
FROM (Income_Statements AS Income_Statements INNER JOIN Balance_Sheets AS Balance_Sheets ON (Income_Statements.Ticker = Balance_Sheets.Ticker) AND (Income_Statements.[Year] = Balance_Sheets.[Year]) AND (Income_Statements.Period = Balance_Sheets.Period)) _
INNER JOIN Cash_Flow_Statements AS Cash_Flow_Statements ON (Balance_Sheets.Ticker = Cash_Flow_Statements.Ticker) AND (Balance_Sheets.[Year] = Cash_Flow_Statements.[Year]) AND (Balance_Sheets.Period = Cash_Flow_Statements.Period)

我需要该变量Formula包含将计算过去 12 个月的自由现金流的等式。这是数学的样子：

自由现金流 TTM = 总和（营运现金流 MRQ1 + 营运现金流 MRQ2 + 营运现金流 MRQ3 + 营运现金流 MRQ4） - 总和（资本支出 MRQ1 + 资本支出 MRQ2 + 资本支出 MRQ3 + 资本支出 MRQ4）

MRQ = 最近一个季度

我需要这个公式在 SQL 中。我该怎么做呢？

更新

根据@Gord Thompson 在下面的回答，我提出了以下代码：

SELECT Ticker, [Year], Period, (SELECT (SUM(su.Net_Cash_Flow_Operating) - SUM(su.Capital_Expenditures)) _
FROM (SELECT Ticker, [Year], Period, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements _
UNION ALL _
SELECT Ticker, [Year] + 1, Period - 4, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements) su _
WHERE su.Ticker = s.Ticker AND su.[Year] = s.[Year] AND (su.Period Between s.Period - 3 And s.Period)) _
AS SalesLast12Months _
FROM Cash_Flow_Statements AS s

当它自己运行时，它会返回我所需要的。但正如我在原始帖子中提到的，我需要能够设置变量Formula以包含 SQL 语句，然后将其插入现有的 SQL 语句中。

所以我试图适应@Gord Thompson 的回答，我想出了这个。

公式：

Formula = “(SELECT (SUM(su.Net_Cash_Flow_Operating) - SUM(su.Capital_Expenditures)) _
FROM (SELECT Ticker, [Year], Period, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements UNION ALL SELECT Ticker, [Year] + 1, Period - 4, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements) su _
WHERE su.Ticker = Cash_Flow_Statements.Ticker AND su.[Year] = Cash_Flow_Statements.[Year] AND (su.Period Between Cash_Flow_Statements.Period - 3 And Cash_Flow_Statements.Period))”

SQL 语句：

"CREATE PROC " & Calculation & " AS SELECT Income_Statements.Ticker, Income_Statements.[Year], Income_Statements.Period, " & Formula & " AS TTM _
FROM (Income_Statements AS Income_Statements _
INNER JOIN Balance_Sheets AS Balance_Sheets ON (Income_Statements.Ticker = Balance_Sheets.Ticker) AND (Income_Statements.[Year] = Balance_Sheets.[Year]) AND (Income_Statements.Period = Balance_Sheets.Period)) _
INNER JOIN Cash_Flow_Statements AS Cash_Flow_Statements ON (Balance_Sheets.Ticker = Cash_Flow_Statements.Ticker) AND (Balance_Sheets.[Year] = Cash_Flow_Statements.[Year]) AND (Balance_Sheets.Period = Cash_Flow_Statements.Period)

这是结果：

同样，这非常接近，但不是我需要的。我相信我知道是什么导致代码在调整时无法工作，但我还不知道如何修复它。在@Gord Thompson 代码中，最后一行是FROM Cash_Flow_Statements AS s. 当我将变量公式插入原始帖子中的现有 SQL 语句时，代码为FROM (Income_Statements AS Income_Statements _ INNER JOIN Balance_Sheets AS Balance_Sheets ON (Income_Statements.Ticker = Balance_Sheets.Ticker) AND (Income_Statements.[Year] = Balance_Sheets.[Year]) AND (Income_Statements.Period = Balance_Sheets.Period)) _ INNER JOIN Cash_Flow_Statements AS Cash_Flow_Statements ON (Balance_Sheets.Ticker = Cash_Flow_Statements.Ticker) AND (Balance_Sheets.[Year] = Cash_Flow_Statements.[Year]) AND (Balance_Sheets.Period = Cash_Flow_Statements.Period). 我几乎可以肯定这就是问题所在，但不知道如何纠正它。

Answer 1

让我们不要太拘泥于列，让我们专注于选择合适的行。

假设我们有一个名为 [SalesSummary] 的表，其中包含

Item      FiscalYear  Quarter  TotalSales
--------  ----------  -------  ----------
bicycles        2011        1         100
bicycles        2011        2         200
bicycles        2011        3         300
bicycles        2011        4         400
bicycles        2012        1         500
bicycles        2012        2         600
bicycles        2012        3         700
bicycles        2012        4         800
ham             2011        1          10
ham             2011        2          20
ham             2011        3          30
ham             2011        4          40
ham             2012        1          50
ham             2012        2          60
ham             2012        3          70
ham             2012        4          80

如果我们想创建一个显示季度数据以及过去 12 个月（当前季度加上前 3 个季度）的总销售额的查询，人们可能会认为我们必须开始IIf()处理“环绕”从一个财政年度到下一个财政年度。幸运的是，我们没有这样做，因为我们可以在下一个财政年度用“假”季度复制相同的数据：2011_Q(4) 变为 2012_Q(0)，2011_Q(3) 变为 2012_Q(-1)，依此类推。

    SELECT
        Item,
        FiscalYear,
        Quarter,
        TotalSales
    FROM SalesSummary
UNION ALL
    SELECT
        Item,
        FiscalYear + 1,
        Quarter - 4,
        TotalSales
    FROM SalesSummary

返回

Item      FiscalYear  Quarter  TotalSales
--------  ----------  -------  ----------
bicycles        2011        1         100
bicycles        2011        2         200
bicycles        2011        3         300
bicycles        2011        4         400
bicycles        2012        1         500
bicycles        2012        2         600
bicycles        2012        3         700
bicycles        2012        4         800
ham             2011        1          10
ham             2011        2          20
ham             2011        3          30
ham             2011        4          40
ham             2012        1          50
ham             2012        2          60
ham             2012        3          70
ham             2012        4          80
bicycles        2012       -3         100
bicycles        2012       -2         200
bicycles        2012       -1         300
bicycles        2012        0         400
bicycles        2013       -3         500
bicycles        2013       -2         600
bicycles        2013       -1         700
bicycles        2013        0         800
ham             2012       -3          10
ham             2012       -2          20
ham             2012       -1          30
ham             2012        0          40
ham             2013       -3          50
ham             2013       -2          60
ham             2013       -1          70
ham             2013        0          80

如果我们将该查询保存为 [SalesUnion] 那么我们可以使用它来生成我们的总数，如下所示

SELECT 
    Item,
    FiscalYear,
    Quarter,
    TotalSales,
    (
        SELECT 
            SUM(su.TotalSales) 
            FROM SalesUnion su 
            WHERE su.Item = s.Item 
                AND su.FiscalYear = s.FiscalYear 
                AND (su.Quarter Between s.Quarter - 3 And s.Quarter)
    ) AS SalesLast12Months
FROM SalesSummary s

或者，如果您不想依赖已保存的查询，您可以一次性完成所有操作：

SELECT 
    Item,
    FiscalYear,
    Quarter,
    TotalSales,
    (
        SELECT 
            SUM(su.TotalSales) 
            FROM 
                (
                        SELECT
                            Item,
                            FiscalYear,
                            Quarter,
                            TotalSales
                        FROM SalesSummary
                    UNION ALL
                        SELECT
                            Item,
                            FiscalYear + 1,
                            Quarter - 4,
                            TotalSales
                        FROM SalesSummary
                ) su 
            WHERE su.Item = s.Item 
                AND su.FiscalYear = s.FiscalYear 
                AND (su.Quarter Between s.Quarter - 3 And s.Quarter)
    ) AS SalesLast12Months
FROM SalesSummary s

无论哪种方式，结果都是

Item      FiscalYear  Quarter  TotalSales  SalesLast12Months
--------  ----------  -------  ----------  -----------------
bicycles        2011        1         100                100
bicycles        2011        2         200                300
bicycles        2011        3         300                600
bicycles        2011        4         400               1000
bicycles        2012        1         500               1400
bicycles        2012        2         600               1800
bicycles        2012        3         700               2200
bicycles        2012        4         800               2600
ham             2011        1          10                 10
ham             2011        2          20                 30
ham             2011        3          30                 60
ham             2011        4          40                100
ham             2012        1          50                140
ham             2012        2          60                180
ham             2012        3          70                220
ham             2012        4          80                260

Answer 2

该变量Formula应包含以下内容：

SELECT (SUM(su.Net_Cash_Flow_Operating) - SUM(su.Capital_Expenditures)) FROM (SELECT Ticker, [Year], Period, Net_Cash_Flow_Operating, Capital_Expenditures FROM Cash_Flow_Statements UNION ALL SELECT Ticker, [Year] + 1, Period - 4, Net_Cash_Flow_Operating, Capital_Expenditures FROM Cash_Flow_Statements) su WHERE su.Ticker = c.Ticker AND su.[Year] = c.[Year] AND (su.Period Between c.Period - 3 And c.Period)