Sql server MS SQL函数-输入参数时的查询条件更改

我正在处理下面的这个SQL函数，但无法根据标志@PastDueFlag（0或1传递）确定如何使代码条件在何处工作

请假定此函数中的整个查询工作正常。我想更改的唯一一行是在1=1和DATEDIFFd、InvoiceDueDate、GETDATE>0下面

当参数@PastDueFlag=1时，我希望在查询中包含此条件，否则在WHERE查询中不包含此行

有办法做到这一点吗

谢谢

ALTER FUNCTION [dbo].[TotalARDueByCompanyID]
(
    -- Add the parameters for the function here
    @CompanyID AS INTEGER,
    @PastDueFlag AS INTEGER
)
RETURNS Float
AS
BEGIN
    DECLARE @TotalARDue AS Float

     SET @TotalARDue = (
        SELECT SUM(CAST(GrandTotal AS NUMERIC(9,2)) + CAST(ISNULL(LinkedTxnAmount, 0) AS NUMERIC(9,2))) AS TotalARDue
        FROM (
            select i.OrderID, InvoiceID, cp.CustomerPO, o.CompanyID, i.CreditMemo
            , CONVERT(VARCHAR(10),(InvoiceDate + (SELECT TermDays FROM dbo.ERP_CompanyTerms WHERE TermID = i.TermID)), 101) AS InvoiceDueDate
            , (isnull(FreightCost,0) + isnull(TaxState,0) + isnull(TaxCounty, 0) + isnull(TaxCity, 0) )
            +
            (SELECT SUM(ExtQty * UnitSell) FROM ERP_InvoiceDetail WHERE invoiceID = i.InvoiceID) as GrandTotal
                --, isnull(i.FreightCost, 0) as FreightCost, i.ShipVia, i.WhoPays, i.Status
            , CONVERT(VARCHAR(10), i.CreatedDate, 101) AS CreatedDate
            , CONVERT(VARCHAR(10), i.InvoiceDate, 101) AS InvoiceDate
            , (select Name from ERP_Company c where c.CompanyID = o.CompanyID) as CompanyName
            , (select first_name + ' ' + last_name from employee where tech_id = i.createdBy) as CreatedBy
            , (SELECT em2.first_name + ' ' + em2.last_name) AS SalesRep
            , (SELECT em2.tech_id) AS SalesRepID
            , o.SOTypeInt AS SOType, em2.WH_RegionID AS Region, i.Status, qv.SFOppt
            , (
                SELECT 
                    (SELECT CASE
                        WHEN CreditMemo = 1 THEN
                            SUM(qi.LinkedTxnAmount) * -1
                        ELSE
                            SUM(qi.LinkedTxnAmount)
                      END
                ) 
                FROM dbo.ERP_Invoice i2
                LEFT JOIN dbo.QuickBooks_InvoiceLinked qi ON RefNumber = CAST(i2.InvoiceID AS VARCHAR(8))
                WHERE 1 = 1
                AND InvoiceID = i.invoiceID --   305763, 304990
                AND LinkedTxnTxnType <> 
                    CASE
                        WHEN i2.CreditMemo = 1 THEN
                            'CreditMemo'
                        ELSE
                            ''
                    END
                GROUP BY CreditMemo
            ) AS LinkedTxnAmount
            from ERP_Invoice i
            LEFT JOIN ERP_Order o on o.OrderID = i.OrderID
            INNER JOIN ERP_Company c on o.CompanyID = c.CompanyID  
            LEFT JOIN Employee em on em.Tech_ID = i.CreatedBy
            LEFT JOIN Employee em2 ON em2.Tech_ID = o.SalesPersonID
            LEFT JOIN ERP_QuoteVer qv ON qv.QuoteVerID = o.QuoteVerID
            LEFT JOIN dbo.ERP_CustomerPO cp ON cp.CustomerPOID = i.CustomerPOID
            where 1 = 1
        ) a
        WHERE
        1 = 1
        AND DATEDIFF("d", InvoiceDueDate, GETDATE()) > 0
        AND CAST(GrandTotal AS NUMERIC(9,2)) + CAST(ISNULL(LinkedTxnAmount, 0) AS numeric(9,2)) > 0
        AND CompanyID = @CompanyID
        AND Status in ('New', 'Completed')
        AND SOType = 'Production'
    )

    -- Return the result of the function
    RETURN @TotalARDue

END

---

我认为您所要做的就是将参数值集成到where子句中：

此外，您不应该在WHERE子句中需要1=1标准

WHERE ( (@PastDueFlag =1 and DATEDIFF("d", InvoiceDueDate, GETDATE()) > 0) or 
        (@PastDueFlag = 0) ) and ...