計算折扣

Question

我有這樣的一個客戶折扣表：

我有一個名爲@Total一個deceared varialbe存儲總量

declare @Total numeric (12,2) 

set @Total = (select Sum(LaborAmt) from #Data 
       group by Co) 

我需要編寫一個查詢，得到正確的根據@Total的折扣率。這就是意味着它應該返回2，如果我的總量是350萬

SELECT  dbo.budCustomerDisc.Customer, dbo.budCustDiscRate.DiscountRate 
FROM   dbo.budCustDiscRate INNER JOIN 
        dbo.budCustomerDisc ON dbo.budCustDiscRate.DiscountID = dbo.budCustomerDisc.DiscountId AND dbo.budCustDiscRate.JBCo = dbo.budCustomerDisc.JBCo 
WHERE  (dbo.budCustomerDisc.Customer = 165) ......... 

對不起，我只是不知道有寫它

Answer 1

這裏的關鍵是，你正在尋找它返回@Total落在BegBillAmt和EndBillAmt之間時的值。您希望它返回正確的DiscountRate。爲此，我們需要一個BETWEEN語句或兩個語句，一個檢查BegBillAmt和一個檢查EndBill Amt的語句。我要說明兩個：使用BETWEEN

第一：

SELECT  dbo.budCustomerDisc.Customer, dbo.budCustDiscRate.DiscountRate 
FROM   dbo.budCustDiscRate INNER JOIN 
       dbo.budCustomerDisc ON dbo.budCustDiscRate.DiscountID = dbo.budCustomerDisc.DiscountId AND dbo.budCustDiscRate.JBCo = dbo.budCustomerDisc.JBCo 

WHERE (dbo.budCustomerDisc.Customer = 165) AND @TOTAL BETWEEN BegBillAmt AND EndBillAmt 

有時之間還不清楚（赫克我不知道它是SQL Server的支持外，或像有一個情況下，他們是數據庫字段，而比靜態變量）。所以這裏是兩個檢查：

SELECT  dbo.budCustomerDisc.Customer, dbo.budCustDiscRate.DiscountRate 
FROM   dbo.budCustDiscRate INNER JOIN 
       dbo.budCustomerDisc ON dbo.budCustDiscRate.DiscountID = dbo.budCustomerDisc.DiscountId AND dbo.budCustDiscRate.JBCo = dbo.budCustomerDisc.JBCo 


WHERE (dbo.budCustomerDisc.Customer = 165) AND BegBillAmt >= @Total AND EndBillAmt <= @Total 

希望這有助於澄清事情給你。

Answer 2

SELECT budCustomerDisc.Customer, budCustDiscRate.DiscountRate 
FROM  budCustDiscRate 
INNER JOIN dbo.budCustomerDisc ON dbo.budCustDiscRate.DiscountID = dbo.budCustomerDisc.DiscountId AND dbo.budCustDiscRate.JBCo = dbo.budCustomerDisc.JBCo 
WHERE  budCustomerDisc.Customer = 165 
      And BegBillAmt <= @Total 
      And EndBillAmt >= @Total