SQL 语句groupby与聚合函数 配合使用

select EmployeeID,SUM(Freight) as 总销售额,
称号=case
    when SUM(Freight) >10000 then '牛人'
	when SUM(Freight) >8000 then '金牌'
	when SUM(Freight) >6000 then '银牌'
	when SUM(Freight) >4000 then '大牌'
	else '快被开除了'	
end
from Orders
group by EmployeeID