访问中每个组sql的前n条记录 [英] Top n records per group sql in access

问题描述

我正在开发一些可以跟踪考试成绩的软件.有多个用户，其详细信息存储在用户表中.然后有一个进度表，该进度表跟踪带有日期和分数的用户的分数.

I am making some software that tracks the scores of a test. There are multiple users, the details of which are stored in a user table. There is then a progress table which tracks a score with the date and the user who's score it is.

我已经可以为所选的用户ID选择3条最新记录

I can already select the 3 most recent records for a chosen userID

SELECT TOP 3 Progress.LoginID, Progress.Score, Progress.[Date Taken]
FROM Progress
WHERE (((Progress.LoginID)=[Enter LoginID:]))
ORDER BY Progress.[Date Taken] DESC;

我可以显示按LoginID分组的所有记录

And I can show all the records grouped by LoginID

SELECT Progress.LoginID, Progress.Score, Progress.[Date Taken]
FROM Progress
GROUP BY Progress.LoginID, Progress.Score, Progress.[Date Taken];

我希望能够在一个查询中显示每个用户的3条最新记录，但我不确定如何使用嵌套查询/子查询来执行此操作.

I want to be able to show the 3 most recent records for each user in one query and I'm unsure of how to use nested queries/subqueries to do so.

用户表的字段名称为:

LoginID   
Forename    
Surname   
DOB   
Guardian Forename     
Guardian Surname      
Telephone Number  

进度表的字段名称为:

ProgressID    
LoginID   
Score     
Date Taken 

任何帮助将不胜感激.

Any help would be appreciated.

推荐答案

一年前，我遇到了类似的问题:

I had a similar problem a year ago: Top 3 per group including 0

使用相同的方法，这将为每个LoginID返回最近的三个日期-如果相同的LoginID有附加日期，则您可能会获得三个以上的记录.

Using the same approach, this will return the latest three dates for each LoginID - you may get more than three records if there are tied dates for the same LoginID.

SELECT  PR1.LogInID, PR1.Score, PR1.[Date Taken]
FROM    Progress AS PR1
WHERE   PR1.[Date Taken] IN (
                        SELECT TOP 3 PR2.[Date Taken]
                        FROM    Progress PR2
                        WHERE   PR2.LoginID = PR1.LoginID
                        ORDER BY PR2.[Date Taken] DESC
                        )
ORDER BY    LoginID, [Date Taken]

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