如何对 SQL 中的每个 UniqueId 仅求和一次？

Question

我有两个 table 大致如下所示：

Table一个

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

和Table乙

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

我希望最后的 table 看起来像这样：

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

我尝试了以下方法，但没有用：

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

有什么想法吗？提前致谢

Answer 1

你可以使用 distinct

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

如果 NetFinanced 金额每 SnapshotTimeId

发生变化，结果将不同

如果您想要最新的 NetFinanced 金额，可以使用 Row_number() 来排序值。

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

Answer 2

您在表 B 中有重复的 NetFinanced 值，当然结果不会给您想要的结果。您需要将 TableA 与 TableB 中的 ContractId 和 NetFinanced 列的唯一值（我假设）连接起来：

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;

Answer 3

像这样尝试

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

如何对 SQL 中的每个 UniqueId 仅求和一次？

How to SUM Only One Time Per UniqueId in SQL?

sql

sql-server

sql-server-2005