如何在SQL中追加平均单价

用以下SQL语句得出的数量及金额
select kubun,VEND,sum(QTY) as 数量,sum(QTY*[P/O@]) as 金额 from [sheet1$a1:v] group by kubun,VEND

现象再追加算出每个VEND的平均单价是多少？（即追加“金额”/“数量”），应该如何修改SQL语句！

select kubun,VEND,sum(QTY) as 数量,sum(QTY*[P/O@]) as 金额,金额/数量 as 平均单价 from [sheet1$a1:v] group by kubun,VEND