按第一列和第二列的最大值选择不同的行

Question

我有下表：

Item           Prod        Company
1.00961.501    PR011798    ditto
1.00961.501    PR012042    ditto
1.00961.501    PR013442    Pika
1.00961.502    PR012043    ditto
1.00961.503    PR011959    ditto
1.00961.503    PR011669    Bulb
1.00961.507    PR014783    ditto
1.00961.507    PR012050    ditto

我想选择按Item分组的所有表，仅采用max Prod 。 像这样：

Item           Prod        Company
1.00961.501    PR012042    ditto
1.00961.502    PR012043    ditto
1.00961.503    PR011959    ditto
1.00961.507    PR014783    ditto

我尝试了以下方法：

SELECT  DISTINCT Item, MAX(Prod)
FROM    DataBase
WHERE   Company = 'ditto'

但这给了我

Column 'Item' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

如果删除MAX子句，则不会返回任何错误，但Item将为每个Prod重复。

任何想法？

编辑

我忘了Where问题中添加Where子句。 当我这样做时，尝试使用Group By而不是Distinct出现以下错误：

Column 'Company' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

Answer 1

您的查询应该像这样；

SELECT  Item, MAX(Prod),Company
FROM    DataBase
WHERE   Company = 'ditto'
GROUP BY Item,Company;

Answer 2

您需要对产品进行分区，然后从该分区中选择一个。

您应该在下面的查询中尝试此操作。

select Item, Prod, Company from 
  (
    select *,
    (ROW_NUMBER() over (partition by Item order by Prod DESC)) as Row from [table_name] 
    where Company = 'ditto'
  ) t where Row = 1