Sql 在查询时返回MAX函数？

我需要找到利润率最高的库存项目，但是我不确定如何做，因为这是在查询中计算的，而不是从表中获取的。 我的脚本如下（使用Oracle11g），当我只需要一个库存项目时，当前返回几个库存项目。请帮忙

SELECT (UPPER(Orderline.StockID) || ' ' || INITCAP(StockDesc)) AS "Item",
CategoryDesc AS "Category",
LocationCity AS "Warehouse",
Quantity AS "Number Sold",
TO_CHAR(Quantity * UnitPrice) AS "Total Income",
TO_CHAR(Quantity * UnitCost) AS "Total Cost",
TO_CHAR((Quantity * UnitPrice) - (Quantity * UnitCost)) AS "Profit"
FROM Orderline INNER JOIN 
(Stock INNER JOIN 
("CATEGORY" INNER JOIN Warehouse
ON "CATEGORY".Warehouse = Warehouse.WarehouseID)
ON Stock.ItemCategory = "CATEGORY".CategoryID)
ON Orderline.StockID = Stock.StockNo
ORDER BY ((Quantity * UnitPrice) - (Quantity * UnitCost)) DESC;

试试这个

select * from (SELECT (UPPER(Orderline.StockID) || ' ' || INITCAP(StockDesc)) AS "Item",
        CategoryDesc AS "Category",
        LocationCity AS "Warehouse",
        Quantity AS "Number Sold",
        TO_CHAR(Quantity * UnitPrice) AS "Total Income",
        TO_CHAR(Quantity * UnitCost) AS "Total Cost",
        TO_CHAR((Quantity * UnitPrice) - (Quantity * UnitCost)) AS "Profit"
        FROM Orderline INNER JOIN 
        (Stock INNER JOIN 
        ("CATEGORY" INNER JOIN Warehouse
        ON "CATEGORY".Warehouse = Warehouse.WarehouseID)
        ON Stock.ItemCategory = "CATEGORY".CategoryID)
        ON Orderline.StockID = Stock.StockNo
        ORDER BY Profit DESC)
        where rownum = 1;

我在评论中看到，您在内部选择上尝试了

rownum=1

。。。这将选择唯一的

项目

，并使用

排序依据

对其进行排序。对一组元素进行排序的方法不多。但是，如果要对所有元素进行排序，可以只选择第一个。这就是这里发生的事情

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查看有关此案例的更多信息

您需要检索最大“利润”字段？将您的查询包装在

select*from（…您在这里的查询…）x中，其中rownum=1

（根据Bacon Bit的建议）@JessRap每…的最高利润。。。。。？项目？类别warehouse？@Andomar，如果没有子查询、内联视图或WITH子句，它将无法工作。在下订单之前，@Matt每件商品的最高利润在哪里？哦，这成功了！非常感谢你！