SQL选择具有多个记录的最大日期 [英] SQL Select Max Date with Multiple records

问题描述

我正在努力查询以吸引最近的条目。我有一个Notes表，其中包含以下列：

I am struggling with a query to pull most recent entries. I have a Notes table that contains the following columns:

BusinessDate
ReportGuid
NoteGuid
Note
NoteDate
NoteAddedBy

BusinessDate，ReportGuid和NoteGuid是PK桌子。该表允许特定的ReportGuid每天有多个笔记。我有另一个表格包含额外的报告信息，将被加入并显示给用户。我试图拉出并显示每个ReportGuid的最新笔记条目。

The BusinessDate, ReportGuid and NoteGuid are the PK on the table. This table allows a specific ReportGuid to have multiple notes per day. I have another table that contains additional Report info that will be joined and displayed for the users. I am trying to pull and display only the most recent note entry for each ReportGuid.

我尝试使用Max（NoteDate），但这只是让我添加了最新的笔记该表不是每个ReportGuid的最新注释。

I tried using Max(NoteDate) but that is only getting me the latest note added to the table not the latest note for each ReportGuid.

任何帮助将不胜感激。

谢谢

更新：

感谢您的帮助：

SELECT N.Note, N.ReportGuid
FROM Tracking.SM_T_Report_Notes N
RIGHT OUTER JOIN
    (
    SELECT ReportGuid, Max(NoteDate) As NoteDate
    FROM Tracking.SM_T_Report_Notes
    GROUP BY ReportGuid
    ) AS ND
    ON  N.NoteDate = ND.NoteDate

推荐答案

您需要通过ReportGuid group并选择 Max（NoteDate）。这将选择每个组的最大值。

You need to group by ReportGuid and select Max(NoteDate). That will select the maximum of each group.

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