SELECT e.EmployeeID,e.LastName + ' ' + e.FirstName AS EmployeeName,COUNT(DISTINCT o.OrderID) AS CountOfOrder,
SUM(od.Quantity * od.UnitPrice) AS Total
FROM Employees e 
LEFT JOIN Orders o ON e.EmployeeID = o.EmployeeID
LEFT JOIN [Order Details] od ON o.OrderID = od.OrderID
GROUP BY e.EmployeeID,e.LastName,e.FirstName
ORDER BY Total DESC;