Sql 如何使用窗口函数获取最大价格及其id？

我有这个疑问

select adate, factoryid, purchid, itemname, max(price) as price 
from tableb where catnum = 9
group by adate, factoryid, purchid, itemname
order by adate, factoryid, purchid, itemname

但我要那排的身份证。所以在一个完美的世界里：

select id, adate, factoryid, purchid, itemname, max(price) as price 
from tableb where catnum = 9
group by adate, factoryid, purchid, itemname
order by adate, factoryid, purchid, itemname

但我知道那是行不通的

所以我试了一下：

select id, adate, factoryid, purchid, itemname, 
       max(price) over(partition by adate, factoryid, purchid, itemname) as price 
from tableb where catnum = 9

那不行。所有ID的价格都是重复的。查询结果集从4000行增加到11000行

---

很明显，我不知怎么把窗口函数搞错了。首先，我做错了什么，其次，当然，我该如何修复它？

我不清楚您为什么想要id，但是。。。

SELECT  *
FROM    (
        SELECT  *,
                ROW_NUMBER() OVER (PARTITION BY adate, factoryid, purchid, itemname ORDER BY price DESC, id DESC) rn
        FROM    tableb 
        WHERE   catnum = 9
        ) q
WHERE   rn = 1

假定

您需要该条件的所有ID

id是表B的PK

那么这可能会起作用：

SELECT tableb.* FROM tableb
INNER JOIN
(
select adate, factoryid, purchid, itemname, max(price) as price 
from tableb where catnum = 9
group by adate, factoryid, purchid, itemname
) AS grouped
ON  tableb.adate = grouped.adate AND
    tableb.factoryid = grouped.factoryid AND
    tableb.purchid = grouped.purchid AND
    tableb.itemname = grouped.itemname AND
    tableb.price = grouped.price
order by tableb.adate, tableb.factoryid, tableb.purchid, tableb.itemname

---

您可以使用Windows版本的

MAX

以及，可从SQL Server 2012+获得：

SELECT DISTINCT adate, factoryid, purchid, itemname, 
       MAX(price) OVER (PARTITION BY adate, factoryid, purchid, itemname) AS price,
       FIRST_VALUE(id) OVER (PARTITION BY adate, factoryid, purchid, itemname
                             ORDER BY price DESC) AS id
FROM tableb 
WHERE catnum = 9
ORDER BY adate, factoryid, purchid, itemname

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id不是唯一确定的。你想要所有的ID还是任何一个？