表值函数，设置变量

Question

我正在研究表值函数，我需要一些帮助。这是我得到的，但看起来 Table-value 函数不喜欢在 RETURN() 语句中声明任何变量。

如您所见，我正在捕获列名称（使用声明/设置变量），但它似乎不适用于值表值。

请告知另一种方法。如果可能，请提供一些示例代码。

谢谢，

Alter FUNCTION getCompanySaleYears()
RETURNS TABLE 
AS
RETURN 
(
    -- //////// START: Get the Years and put them in the String for columns /////////
    Declare @StartYear INT, @EndYear INT, @sql VARCHAR(MAX)
    Declare @StrYears varchar(max);
    Set @StartYear = 2011;
    SET @EndYear = Year(Getdate());

    SET @StrYears = ''

    WHILE @StartYear <= @EndYear
    BEGIN
        SET @StrYears = @StrYears + ', [' + cast(@StartYear as varchar(10)) + ']'
        SET @StartYear = @StartYear + 1 
    END

    Select @StrYears = (SUBSTRING(@StrYears, 2, LEN(@StrYears)) )
    -- //////// START: Get the Years and put them in the String for columns /////////


    SET @sql = N'
    SELECT CompanyID, ' + @StrYears + '
    FROM (
        SELECT CompanyID, SalesYear, SUM(TotalSO) AS TotalSO FROM (
            SELECT c.CompanyID, o.OrderID, YEAR(o.CreatedDate) AS SalesYear
            , ISNULL((Select SUM(ExtQty * UnitSell) FROM dbo.OrderDetail WHERE OrderID = o.OrderID  ), 0) AS TotalSO
            FROM dbo.Company c
            LEFT JOIN Order o ON o.CompanyID = c.CompanyID
            WHERE 1 = 1
            --AND c.CompanyID = o2.CompanyID
            AND YEAR(o.CreatedDate) BETWEEN ''2011'' And Year(Getdate())

        ) z
        GROUP BY CompanyID, SalesYear
    ) x
    PIVOT
    (
        Sum(TotalSO)
        FOR SalesYear
        IN (
            ' + @StrYears + ' 
        )   
    ) AS pvtSalesYear
    '

    PRINT @sql
    EXEC (@sql)
)

Answer 1

不幸的是，这不能使用 TVF 完成，因为 SQL 期望的是硬返回模式，而不是您所做的灵活模式。

你可以在 TVF 中有变量，你只需要其他语法

ALTER FUNCTION ...() RETURNS @t TABLE(CompanyID int, ...) AS BEGIN
  INSERT @t(CompanyID,...) SELECT companyid,... FROM dbo.Company c LEFT JOIN...
  RETURN;
END;