Question

我有一张订购的物品表。表字段：PONumber，OrderDate，itemNumber，Description，Cost

由于我可以在不同日期多次订购商品，因此我想返回最近的日期，但仍然包含所有字段。

表格

PONumber    OrderDate   itemNumber  Description Cost
123         01/01/2016  A235        Bolt        1.13
142         02/22/2016  A235        Blot        2.10
166         03/01/2016  A444        Screw       1.22
411

返回

PONumber    OrderDate   itemNumber  Description Cost
142         02/22/2016  A235        Blot        2.10
166         03/01/2016  A444        Screw       1.22

我尝试了一个完整的查询，但是我必须删除“费用”字段，否则它会显示所有记录，我需要显示费用。

SELECT PONumber, Max(OrderDate), itemNumber, Description, Cost
FROM tblItemsOrdered
GROUP BY PONumber, OrderDate, itemNumber, Description, Cost;

Answer 1

查找子查询中每个项目的最新订单日期，并将其与原始表格连接，如下所示：

header {
    padding-top: 1px;
}

请注意，如果所有这些行都有最新的orderDate，这将为同一itemNumber返回多行。

编辑：

select t1.*
from tblItemsOrdered t1
inner join (
    SELECT itemNumber, Max(OrderDate) as Max_OrderDate
    FROM tblItemsOrdered
    GROUP BY itemNumber
) t2 on t1.itemNumber = t2.itemNumber
and t1.OrderDate = t2.Max_OrderDate;

或者如果PONumber是唯一的：

select t1.*
from tblItemsOrdered t1
inner join (
    select t1.itemNumber, t1.OrderDate, max(t1.PONumber) as max_PONumber
    from tblItemsOrdered t1
    inner join (
        SELECT itemNumber, Max(OrderDate) as Max_OrderDate
        FROM tblItemsOrdered
        GROUP BY itemNumber
    ) t2 on t1.itemNumber = t2.itemNumber
    and t1.OrderDate = t2.Max_OrderDate
    group by t1.itemNumber, t1.OrderDate
) t2 on t1.itemNumber = t2.itemNumber
and t1.PONumber = t2.max_PONumber
and t1.OrderDate = t2.OrderDate;

Answer 2

这不是group by。您想要所有列，请考虑where进行过滤：

select o.*
from tblItemsOrdered as o
where o.OrderDate = (select max(o2.OrderDate)
                     from tblItemsOrdered as o2
                     where o2.itemNumber = o.itemNumber
                    );

注意：如果该项目在最近的日期被多次订购，那么这将返回所有行。

MS Access：查询分组依据，但显示所有字段

2 个答案:

编辑：