如何在SQL中每次只有一次SUM SUM？

表A

DocumentId (*is unique) DocumentDate 
1      2016-01-01 
2      2016-01-01 
3      2016-02-01 
4      2016-03-01

和表B

ContractId SnapshotTimeId NetFinanced 
1   20160231  300 
1   20160331  300 
1   20160431  300 
2   20160231  450 
2   20160331  450 
2   20160431  450 
3   20160331  500 
3   20160431  500 
4   20160431  150

我想決賽桌看起來是這樣的：

DocumentDate NetFinanced 
2016-01-01 750 
2016-02-01 500 
2016-03-01 150

我試過以下它不起作用：

SELECT A.DocumentDate, SUM(B.NetFinanced) 
FROM A 
JOIN B on B.ContractId=A.DocumentId 
GROUP BY A.DocumentDate

任何想法？在此先感謝

來源

2016-09-23 Liviu Anca

你應該閱讀有關'GROUP BY'。 – DavidG

是日期時間還是日期字段？ – GuidoG

輸出結果如何？你能解釋一下嗎？ – Susang

你可以使用不同的

SELECT A.DocumentDate, 
     SUM(B.NetFinanced) 
FROM A 
     JOIN (SELECT DISTINCT 
         ContractId, 
         NetFinanced 
       FROM  B 
      ) B ON B.ContractId = A.DocumentId 
GROUP BY A.DocumentDate

這樣做的結果會有所不同，如果NetFinanced量每SnapshotTimeId

，如果你想在最近NetFinanced量，您可以使用ROW_NUMBER改變（）來訂購這些值。

SELECT A.DocumentDate, 
     SUM(B.NetFinanced) 
FROM A 
     JOIN (SELECT ROW_NUMBER() OVER (PARTITION BY ContractId ORDER BY SnapshotTimeId DESC) Rn, 
         ContractId, 
         NetFinanced 
       FROM  B 
      ) B ON B.ContractId = A.DocumentId AND B.Rn = 1 
GROUP BY A.DocumentDate

來源

2016-09-23 15:28:18 JamieD77

你有你想要什麼NetFinanced重複值表B，當然結果不會給你。您需要從表B加入與ContractId和NetFinanced列中的唯一值（我假設）表A：

SELECT A.DocumentDate, 
     SUM(B.NetFinanced) NetFinanced 
FROM dbo.TableA A 
INNER JOIN (SELECT DISTINCT ContractId, NetFinanced 
      FROM dbo.TableB) B 
    ON A.DocumentId = B.ContractId 
GROUP BY A.DocumentDate;

來源

2016-09-23 15:28:37 Lamak

嘗試像這樣

SELECT A.DocumentDate, SUM(B.NetFinanced) 
FROM A 
JOIN (SELECT MAX(ContractId) ContractId, MAX(SnapshotTimeId)SnapshotTimeId, 
      MAX(NetFinanced)NetFinanced 
     FROM B GROUP BY ContractId) B ON B.ContractId = A.DocumentId 
GROUP BY A.DocumentDate

來源

2016-09-23 15:34:57

如何在SQL中每次只有一次SUM SUM？

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