你是某销售组织的数据库开发人员, 你的数据库有一个名为Sales表, 此表包括了来自销售人员的销售订单概要信息.销售经理要求你创建一个销售额排在前20位的销售人员报表, 你该使用哪个查询来完成这个任务( )

A、 SELECT TOP 20 PERCENT LastName, FirstName, SUM (OrderAmount) AS ytd
FROM sales
GROUP BY LastName, FirstName
ORDER BY 3 DESC
B、 SELECT LastName, FirstName, COUNT(*) AS sales
FROM sales
GROUP BY LastName, FirstName
HAVING COUNT (*) > 20
ORDER BY 3 DESC
C、 SELECT TOP 20 LastName, FirstName, MAX(OrderAmount) AS ytd
FROM sales
GROUP BY LastName, FirstName
ORDER BY 3 DESC
D、 SELECT TOP 20 LastName, FirstName, SUM (OrderAmount) AS ytd
FROM sales
GROUP BY LastName, FirstName
ORDER BY 3 DESC


【参考答案】

参考D