MS Access-提取单个值进行计算

Question

这是一个与MS Access相关的问题。

我把抵押品分了50次，因为我的汇率表中有50行。。。然而，SELECT语句应该只提取与CurrencyCode="EUR"相关的值。如何更改以下语句，使除法只应用一次？

SELECT tbl_A.Security, tbl_A.Typ, Sum(([Collateral]/(SELECT tblExchangeRates.RateToUSD
FROM tblExchangeRates
WHERE (((tblExchangeRates.CurrencyCode)="EUR"))))) AS CollateralUSD
FROM tbl_A, tblExchangeRates
GROUP BY tbl_A.Security, tbl_A.Typ
HAVING (((tbl_A.Typ)="PR"));

Answer 1

看起来这就是我想要的，只是一个Alias。SQL大师，欢迎您的评论。

SELECT tbl_A.Security, Sum(([Collateral]/[RateToUSD])) AS CollateralUSD
FROM tbl_A, (SELECT RateToUSD
    FROM tblExchangeRates
    WHERE CurrencyCode = 'EUR')  AS MyAliasQ
GROUP BY tbl_A.Security
HAVING (((tbl_A.Typ)="PR"));