Question

I have a table containing multiple computer names and the date of a connection. Here’s an example.

ID    Computer         User         Date         
------------------------------------------------
1      O-1234          User1         2010-07-08        
2      O-1234          User2         2010-08-24           
3      O-1234          User2         2010-09-25
4      O-1555          User3         2010-08-24           
5      O-1555          User3         2010-09-25      

I would like to be able to only select the last 2 or 3 connections for each computer. Also, I can’t modify the table. Anybody have an idea ?

Thank you

EDIT: It’s a MS Access mdb file

EDIT”: Since RANK OVER() can’t be used in MS Access, would it be possible to use a temporary table to do the job ?

Answer 1

SELECT *
FROM (
    SELECT ID, Computer, User, Date,
    RANK() OVER ( PARTITION BY Computer ORDER BY Date DESC) AS RowNumber
    FROM YourTable)
WHERE RowNumber <= 3

EDIT: Oh… it’s Access.

I don’t have access to… er… Access, but can try this instead?

SELECT
    logins.ID,
    logins.Computer,
    logins.User,
    logins.Date,
    COUNT(*)
FROM
    YourTable logins INNER JOIN
    YourTable Subsequentlogins ON
        logins.Computer = Subsequentlogins.Computer
        AND logins.Date <= Subsequentlogins.Date
GROUP BY
    logins.ID,
    logins.Computer,
    logins.User,
    logins.Date
HAVING COUNT(*) <= 3