groupe par une valeur d'une autre colonne

Question

J'ai la table des articles ai eu

ID identity autoincement, IDArticle: nvarchar(100) ,IDCar nvarchar(100), createddate 

Comment convertir ceci:

SELECT IDCar , MAX(createddate) 
FROM Articles 
GROUP BY IDCar 

pour obtenir IDArticle par exemple:

1 art1 BWM 5-21-2010 
2 art2 BMW 5-24-2010 
3 art3 BMW 5-31-2010 
4 art4 Porshe 5-31-2010 
5 art5 Porshe 6-1-2010 

résultat Expecting est:

art3 
art5 

Il est pas reproduit avec: Sql query number of occurance

Answer 1

SELECT a.IDArticle 
FROM 
(
    SELECT IDCar , MAX(createddate) as max_date 
    FROM Articles 
    GROUP BY IDCar 
) max 
INNER JOIN Articles a ON a.IDCar = max.IDCar and a.createddate = max.max_date 

Answer 2

SELECT outerTable.IDArticle 
FROM Articles outerTable 
WHERE outerTable.createddate = 
    (SELECT MAX(innerTable.createddate) 
    FROM Articles innerTable 
    WHERE outerTable.IDCar = innerTable.IDCar 
    GROUP BY innerTable.IDCar) 

Answer 3

WITH ArticlesMaxDate (IDCar, MaxCreatedDate) AS 
(
    SELECT 
     IDCar , MAX(createddate) AS MaxCreatedDate 
    FROM 
     Articles 
    GROUP BY 
     IDCar 
) 
SELECT 
    a.IDcar 
    , a.IDArticle 
    , amd.MaxCreatedDate 
FROM 
    Articles a 
    INNER JOIN ArticlesMaxDate amd ON amd.IDCar = a.IDCar 
     AND amd.MaxCreatedDate = a.createddate