--按订单数
select User.UserID,
    min(User.UserName) 姓名,
    count([Order].OrderID) 订单数量
from [User] left join [Order] on User.UserID=[Order].UserID
group by User.UserID
order by 订单数量 desc;
--按销售数
select User.UserID,
    min(User.UserName) 姓名,
    sum(OrderUnit*OrderNum) 销售数量
from [User] left join [Order] on User.UserID=[Order].UserID
group by User.UserID
order by 销售数量 desc;

------解决方案--------------------
SQL code
--各个产品的销量情况
select b.[UserName],a.[OrderName],sum(a.[OrderUnit]*a.[OrderNum]) 销量 from [Order] a,[User] b
where a.[UserID]=b.[UserID]
group by b.[UserName],a.[OrderName]
order by a.[OrderName],sum(a.[OrderUnit]*a.[OrderNum]) desc

--总的销量情况
select b.[UserName],sum(a.[OrderUnit]*a.[OrderNum]) 销量 from [Order] a,[User] b
where a.[UserID]=b.[UserID]
group by b.[UserName]
order by sum(a.[OrderUnit]*a.[OrderNum]) desc

------解决方案--------------------
探讨


引用:
/*
排名                   UserID      UserName 销售
-------------------- ----------- -------- -----------
1                    2           小二       15
2                    3           ……