SQL Server组按顺序排列

Question

I have a single table which I need to pull back the 5 most recent records based on a userID and keying off of documentID (no duplicates). Basically, I'm tracking visited pages and trying to pull back the 3 most recent by user.

Sample data:

╔══════════════════════════════════════════════╗
║UserID   DocumentID   CreatedDate             ║
╠══════════════════════════════════════════════╣
║  71         22       2013-09-09 12:19:37.930 ║
║  71         25       2013-09-09 12:20:37.930 ║
║  72          1       2012-11-09 12:19:37.930 ║
║  99         76       2012-10-10 12:19:37.930 ║
║  71         22       2013-09-09 12:19:37.930 ║
╚══════════════════════════════════════════════╝

Desired query results if UserID = 71:

╔══════════════════════════════════════════════╗
║UserID    DocumentID  CreatedDate             ║
╠══════════════════════════════════════════════╣
║  71         25       2013-09-09 12:20:37.930 ║
║  71         22       2013-09-09 12:19:37.930 ║
╚══════════════════════════════════════════════╝

Answer 1

SELECT TOP 3 UserId, DocumentId, MAX(CreatedDate)
FROM MyTable
WHERE UserId = 71
GROUP BY UserId, DocumentId
ORDER BY MAX(CreatedDate) DESC

Answer 2

You could try this:

SELECT DISTINCT USERID, 
                DOCUMENTID, 
                MAX(CREATEDDATE) 
                  OVER ( 
                    PARTITION BY USERID, DOCUMENTID) CREATEDDATE 
FROM   MYTABLE 
WHERE  USERID = 71 

Take a look at the working example on SQL Fiddle .

Good Luck!

Answer 3

You could try using a CTE and ROW_NUMBER .

Something like

;WITH Vals AS (
    SELECT UserID, 
           DocumentID, 
           ROW_NUMBER() OVER(PARTITION BY UserID, DocumnentID ORDER BY CreatedDate DESC) RowID
    FROM MyTable
)
SELECT TOP 3 *
FROM Vals
WHERE UserID = 71
AND RowID = 1

Answer 4

Select USERID,DOCUMENT ID 
FROM yourtable
QUALIFY ROW_NUMBER OVER(Partition by user id ORDER By document id Desc)<6

This works in Teradata. Hope this works in Sql Server too as its mainly ANSI SQL.