计算折扣

Question

我有这样的一个客户折扣表：

我有一个名为@Total一个deceared varialbe存储总量

declare @Total numeric (12,2) 

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

我需要编写一个查询，得到正确的根据@Total的折扣率。这就是意味着它应该返回2，如果我的总量是350万

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) ......... 

对不起，我只是不知道有写它

Answer 1

这里的关键是，你正在寻找它返回@Total落在BegBillAmt和EndBillAmt之间时的值。您希望它返回正确的DiscountRate。为此，我们需要一个BETWEEN语句或两个语句，一个检查BegBillAmt和一个检查EndBill Amt的语句。我要说明两个：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 

有时之间还不清楚（赫克我不知道它是SQL Server的支持外，或像有一个情况下，他们是数据库字段，而比静态变量）。所以这里是两个检查：

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 

希望这有助于澄清事情给你。

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