Sql 基于第二列值对列中的不同行求和

我有一个订单表（简化）

我正试图在此表上创建一个报告，我希望得到如下结果：

SalesPersonId   TotalCAD    TotalUSD
1               12,345.00   6,789.00
2               7,890.00    1,234.00

我不希望进行自连接（也许我过早地进行了优化，但这似乎效率低下），即：

但是我想不出其他方法来做这件事，有什么想法吗？

试试这个：

SELECT SalesPersonId, 
       SUM(CASE WHEN CurrencyID = 1 THEN SaleAmount ELSE 0 END) as CAD, 
       SUM(CASE WHEN CurrencyID = 2 THEN SaleAmount ELSE 0 END) as USD
FROM ORDERS

使用案例块：

SELECT
  SalesPersonId,
  SUM(
    CASE CurrencyID
      WHEN 1 THEN SaleAmount
      ELSE 0
    END
  ) AS TotalCAD,
  SUM(
    CASE CurrencyID
      WHEN 2 THEN SaleAmount
      ELSE 0
    END
  ) AS TotalUSD
FROM Orders
GROUP BY SalesPersonId

---

考虑试用标量值函数（SQL Server 2000或更高版本）

然后执行类似这样的SQL以获得结果（假设您也有一个单独的Salesors表，或者使用SELECT DISTINCT SALERSONID….FROM Orders）：

---

一定要运行查询计划，看看它与此处建议的其他可能性相比是否符合您的需要，尤其是在处理大量数据的情况下。

简直太棒了。一段时间以来我一直想知道如何做到这一点。谢谢

SELECT SalesPersonId, 
       SUM(CASE WHEN CurrencyID = 1 THEN SaleAmount ELSE 0 END) as CAD, 
       SUM(CASE WHEN CurrencyID = 2 THEN SaleAmount ELSE 0 END) as USD
FROM ORDERS

SELECT
  SalesPersonId,
  SUM(
    CASE CurrencyID
      WHEN 1 THEN SaleAmount
      ELSE 0
    END
  ) AS TotalCAD,
  SUM(
    CASE CurrencyID
      WHEN 2 THEN SaleAmount
      ELSE 0
    END
  ) AS TotalUSD
FROM Orders
GROUP BY SalesPersonId

CREATE FUNCTION dbo.GetOrdersSumByCurrency
(   
    @SalesPersonID INT, @CurrencyID INT 
)
RETURNS DECIMAL(10, 2) 
AS
BEGIN
    DECLARE @Sum DECIMAL(10, 2) 

    SELECT @Sum = ISNULL(SUM(SalesAmount), 0) FROM dbo.Orders 
    WHERE SalespersonID=@SalesPersonID AND CurrencyID = @CurrencyID

    RETURN @Sum

END

    SELECT SalesPersonId, 
dbo.GetOrdersSumByCurrency(SalesPersonId, 1) AS SumUSD, dbo.GetOrdersSumByCurrency(SalesPersonId, 2) AS SumCAD 
    FROM SalesPersons