SELECT s.BusinessEntityID AS 'ID Vendedor',
    SUM(S2008.SalesQuota) AS 'Total Quota Ventas 2008',
    SUM(S2007.SalesQuota) AS 'Total Quota Ventas 2007'
FROM Sales.SalesPerson AS S
    LEFT OUTER JOIN Sales.SalesPersonQuotaHistory AS S2008
        ON S.BusinessEntityID = S2008.BusinessEntityID
            AND YEAR(S2008.QuotaDate) = 2008
        LEFT OUTER JOIN Sales.SalesPersonQuotaHistory AS S2007
            ON S.BusinessEntityID = S2007.BusinessEntityID
                AND YEAR(s2007.QuotaDate) = 2007
GROUP BY S.BusinessEntityID;