Vous devez SUM
puis ORDER BY
cette valeur récapitulative :
SELECT TOP 3 ProductID, SUM(Quantity) as qSum
FROM Table
GROUP BY ProductID
ORDER BY qSum DESC
Vous devez SUM
puis ORDER BY
cette valeur récapitulative :
SELECT TOP 3 ProductID, SUM(Quantity) as qSum
FROM Table
GROUP BY ProductID
ORDER BY qSum DESC