SQL从3个表中选择总和

Question

我正在使用Microsoft SQL Server 2008 R2。我想加入3个表格，然后按期（月）分组，并获得每个期间和最大汇率的所有金额的总和。我在下面有这个SQL语句。

SELECT T2.Name AS Period, T1.LineTotal AS Amount, T0.DocRate AS ExchangeRate 
FROM OINV T0 INNER JOIN INV1 T1 ON T0.DocEntry = T1.DocEntry 
INNER JOIN dbo.OFPR AS t2 ON T1.FinncPriod = T2.AbsEntry 
WHERE T0.DocStatus = 'O' 

示例结果从上述查询：

Period   Amount  ExchangeRate 
Year 2012-01 500.000000 83.000000 
Year 2012-01 1000.000000 1.000000 
Year 2012-02 2000.000000 1.000000 
Year 2012-02 3000.000000 1.000000 
Year 2012-02 2500.500000 1.000000 
Year 2012-03 500.000000 1.000000 
Year 2012-03 1500.000000 94.000000 
Year 2012-04 4000.000000 1.000000 
Year 2012-04 2000.000000 1.000000 
Year 2012-04 2000.000000 1.000000 

我希望得到如下结果：

Period   Amount  ExchangeRate 
Year 2012-01 1500.000000 83.000000 
Year 2012-02 7500.000000 1.000000 
Year 2012-03 2000.000000 94.000000 
Year 2012-04 8000.000000 1.000000 

如何修改我的查询，以获得上述结果？

Answer 1

试试这个：

通过

SELECT T2.NAME AS PERIOD 
     , SUM(T1.LINETOTAL) AS AMOUNT 
     , MAX(T0.DOCRATE) AS EXCHANGERATE 
FROM OINV T0 INNER JOIN INV1 T1 
     ON T0.DOCENTRY = T1.DOCENTRY 
     INNER JOIN DBO.OFPR AS T2 
     ON T1.FINNCPRIOD = T2.ABSENTRY 
WHERE T0.DOCSTATUS = 'O' 
GROUP BY T2.NAME 

Answer 2

只是做小组尝试使用SUM，MAX和GROUP BY。

喜欢的东西

SELECT T2.Name AS Period, 
     SUM(T1.LineTotal) AS Amount, 
     MAX(T0.DocRate) AS ExchangeRate 
FROM OINV T0 INNER JOIN 
     INV1 T1 ON T0.DocEntry = T1.DocEntry INNER JOIN 
     dbo.OFPR AS t2 ON T1.FinncPriod = T2.AbsEntry 
WHERE T0.DocStatus = 'O' 
GROUP BY T2.Name