根据另一列选择最大日期

Question

我有一个数据集，其中有与发票编号关联的不同提交 ID 和提交日期时间。我试图为每个发票编号仅选择具有最近提交日期时间的行。示例数据如下，期望的结果是仅返回第 2 行

我尝试过的示例查询如下：

SELECT TOP 1000 S.SubissionID
,BookingID
,InvoiceNumber
,InvoiceDate
,NumberofServices
,SubmissionDateTime
FROM [dbo].[Submission] S
JOIN [dbo].[SubmissionInvoice] SI on S.SubmissionID = SI.SubmissionID
INNER JOIN (SELECT MAX(SubmissionDateTime maxdate FROM [dbo].[Submission] m on m.maxdate = s.SubmissionDateTime

这仅返回具有最新提交日期时间的记录，无论发票编号或提交ID如何。

 SELECT TOP 1000 S.SubissionID
    ,BookingID
    ,InvoiceNumber
    ,InvoiceDate
    ,NumberofServices
    ,SubmissionDateTime
    FROM [dbo].[Submission] S
    JOIN [dbo].[SubmissionInvoice] SI on S.SubmissionID = SI.SubmissionID
    and SubmissionDateTime = (
    SELECT MAX (SubmissionDateTime) 
    FROM [dbo].[Submission] as B
    WHERE S.SubmissionID = B.SubmissionID)

这个最大日期过滤似乎没有做任何事情，结果看起来就像我根本没有包含查询的那部分一样。

Answer 1

如果您的 RDBM 支持，您可以使用像 row_number() 这样的窗口函数。这是一个例子

SELECT SubissionID
       ,BookingID
       ,InvoiceNumber
       ,InvoiceDate
       ,NumberofServices
       ,SubmissionDateTime
FROM (
SELECT S.SubissionID
    ,BookingID
    ,InvoiceNumber
    ,InvoiceDate
    ,NumberofServices
    ,SubmissionDateTime
    ,row_number() over(partition by InvoiceNumber order by SubmissionDateTime DESC) AS RN
FROM [dbo].[Submission] S
JOIN [dbo].[SubmissionInvoice] SI 
  on S.SubmissionID = SI.SubmissionID) t
WHERE RN = 1