MySql：在联接表中返回MAX值

Question

我这里有3张桌子。 有客户，订单和客户订购的物品。 这些被命名为：CustomersTbl，OrdersTbl，OrderedItemTbl。

我正在安排所有订单及其总价，并显示发出订单名称的客户。

select * from productstbl;
select * from ordereditemtbl;
select * from orderstbl;

select 
    ordereditemtbl.ItemID,
    customerstbl.CustomerID,
    customerstbl.FirstName,
    orderstbl.OrderID,
    orderstbl.OrderDate,
    sum(ordereditemtbl.amount * productstbl.Price) as totalPrice
from
    ordereditemtbl
        inner join
    ProductsTbl ON ordereditemtbl.productID = productstbl.productID
        inner join
    orderstbl ON ordereditemtbl.orderID = ordereditemtbl.orderID
        inner join
    customerstbl ON customerstbl.customerID = orderstbl.customerID#'2'
group by ordereditemTbl.OrderID
order by totalPrice desc;

现在，我想单独显示具有最高TotalPrice的订单。 如何获得最大值？ 有没有办法使用MAX（）函数？

Answer 1

让我们来看看。 查看是否可行：

SELECT * FROM 
(
select 
    ordereditemtbl.ItemID,
    customerstbl.CustomerID,
    customerstbl.FirstName,
    orderstbl.OrderID,
    orderstbl.OrderDate,
    sum(ordereditemtbl.amount * productstbl.Price) as totalPrice,
    @rownum AS row_number
from
    ordereditemtbl
        inner join
    ProductsTbl ON ordereditemtbl.productID = productstbl.productID
        inner join
    orderstbl ON ordereditemtbl.orderID = ordereditemtbl.orderID
        inner join
    customerstbl ON customerstbl.customerID = orderstbl.customerID#'2'
        inner join
    (SELECT @rownum := 0) dummy
group by ordereditemTbl.OrderID
ORDER BY totalPrice desc;
)
WHERE row_number=0

这会分配一个行号并选择第一行。

干杯，拉姆

Answer 2

根据abl的建议，我在代码末尾添加了以下内容：

order by totalPrice desc LIMIT 1;

显示所创建表的第一行，以降序显示。 谢谢！