SQL如何將2個查詢合併爲一個

Question

我有2個查詢返回有關貿易債務人的結果。所有貿易債務人每月首次返還金額，30天后所有貿易債務人每月返還二次金額。

1查詢

SELECT T2.Name AS Period, 
     SUM(T1.LineTotal) AS CurrentAmount, 
     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' AND t0.DocDate BETWEEN '2007-01-01' AND '2007-12-01' 
GROUP BY T2.Name 

第二查詢

SELECT T2.Name AS Period, 
     SUM(T1.LineTotal) AS NonCurrentAmount,   
     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' AND DATEDIFF(day,t0.DocDate,t0.DocDueDate)>30 
     AND t0.DocDate BETWEEN '2007-01-01' AND '2007-12-01' 
GROUP BY T2.Name 

如何合併2級以上的查詢爲一體，使得生成的查詢將返回結果4列; Period, CurrentAmount, NonCurrentAmount and exchange rate.

Answer 1

你可以在where條款移動差與case聲明：

SELECT T2.Name AS Period, 
     SUM(T1.LineTotal) AS CurrentAmount, 
     MAX(T0.DocRate) AS ExchangeRate1, 
     SUM(case when DATEDIFF(day,t0.DocDate,t0.DocDueDate) > 30 
      then T1.LineTotal end) AS NonCurrentAmount,   
     MAX(case when DATEDIFF(day,t0.DocDate,t0.DocDueDate) > 30 
      then T0.DocRate end) AS ExchangeRate2 
FROM OINV T0 
JOIN INV1 T1 
ON  T0.DocEntry = T1.DocEntry 
JOIN dbo.OFPR AS t2 ON T1.FinncPriod = T2.AbsEntry 
WHERE T0.DocStatus = 'O' 
     AND t0.DocDate BETWEEN '2007-01-01' AND '2007-12-01' 
GROUP BY 
     T2.Name