TSQL分组时选择最小和最大行

Question

可以说我有一个包含许多行的表,如下所示:

ID        Range         Range_begining        Profit
----------------------------------------------------
 1    (100-150)                    100           -20
 2    (200-250)                    200          40.2
 3    (100-150)                    100           100
 4    (450-500)                    450           -90
 ...

我正在做一个像这样的简单查询:

SELECT max([Range]) AS 'Range'
     , count(ID) AS 'Count'
     , round(avg([Profit]), 2) AS 'AVG Profit'
    FROM
        Orders
    GROUP BY
        Range_begining

运行此查询后,我得到如下结果:

Range        Count        AVG Profit
------------------------------------
(100-150)        2                40
(200-250)        1              40.2
(450-500)        1               -90
 ...

非常简单 :)

我现在需要做的是选择具有最小和最大利润的行,其中count大于10(这是一个参数)

我能够获得最低价值:

SELECT TOP 1 [Range], [AVG Profit] FROM (
     SELECT max([Range]) AS 'Range'
         , count(ID) AS 'Count'
         , round(avg([Profit]), 2) AS 'AVG Profit'
        FROM
            Orders
        GROUP BY
            Range_begining) X
WHERE
    [Count]>10
ORDER BY 
    [AVG Profit] ASC --or DESC if I want max profit

我正在考虑UNION使用ORDER BY DESC进行上述查询,但它不是最佳解决方案.

我需要做的事情:
选择2行:一行最小,第二行,按范围分组时最大AVG利润.

编辑: 如果我添加2个移动列到我的主数据表,如下所示:

ID        Range         Range_begining        Profit        OrderDate     Company
---------------------------------------------------------------------------------
 1    (100-150)                    100           -20        2012-01-02          1
 2    (200-250)                    200          40.2        2012-03-22          0
 3    (100-150)                    100           100        2012-02-05          0
 4    (450-500)                    450           -90        2012-05-12          1
 ...

然后尝试添加另外两个条件,如下所示:

; with ordering as (
  SELECT max([Range]) AS 'Range'
     , count(ID) AS 'Count'
     , round(avg([Profit]), 2) AS 'AVG Profit'
     , row_number() over (order by avg([Profit])) rn_min
     , row_number() over (order by avg([Profit]) desc) rn_max
    FROM
        Orders
    GROUP BY
        Range_begining
    HAVING COUNT(ID) > 10
    AND [Company]=@company
    AND (@from= '' OR [OrderDate]>=@from)
    AND (@to= '' OR [OrderDate]<=@to)
)
select [range], [count], [avg profit]
  from ordering
 where (rn_max = 1 or rn_min = 1)

我收到错误,因为[公司]和[订单日期]

在HAVING子句中无效,因为它不包含在聚合函数或GROUP BY子句中.

我怎样才能解决这个问题？

EDIT2搞定 了!

; with ordering as (
  SELECT max([Range]) AS 'Range'
     , count(ID) AS 'Count'
     , round(avg([Profit]), 2) AS 'AVG Profit'
     , row_number() over (order by avg([Profit])) rn_min
     , row_number() over (order by avg([Profit]) desc) rn_max
    FROM
        Orders
    WHERE
    [Company]=@company
    AND (@from= '' OR [OrderDate]>=@from)
    AND (@to= '' OR [OrderDate]<=@to)
    GROUP BY
        Range_begining
    HAVING COUNT(ID) > 10
)
select [range], [count], [avg profit]
  from ordering
 where (rn_max = 1 or rn_min = 1)

编辑3 我可以返回另一个列,其中包含以下描述:

Range        AVG Profit               Description
-------------------------------------------------
(200-250)          40.2           Max profit here
(450-500)           -90     Min profit, well done

编辑4 快速回答(基于@NikolaMarkovinović答案):

; with ordering as (
  SELECT max([Range]) AS 'Range'
     , count(ID) AS 'Count'
     , round(avg([Profit]), 2) AS 'AVG Profit'
     , row_number() over (order by avg([Profit])) rn_min
     , row_number() over (order by avg([Profit]) desc) rn_max
    FROM
        Orders
    WHERE
    [Company]=@company
    AND (@from= '' OR [OrderDate]>=@from)
    AND (@to= '' OR [OrderDate]<=@to)
    GROUP BY
        Range_begining
    HAVING COUNT(ID) > 10
)
    SELECT
    CASE WHEN rn_max=1 THEN 'This is max' ELSE 'Min' END AS 'Description'
    ,[range]
    ,[count]
    ,[avg profit]
    FROM ordering
    WHERE (rn_max = 1 or rn_min = 1)

Answer 1

您可以使用窗口函数立即执行此操作:

; with ordering as (
  SELECT max([Range]) AS 'Range'
     , count(ID) AS 'Count'
     , round(avg([Profit]), 2) AS 'AVG Profit'
     , row_number() over (order by avg([Profit])) rn_min
     , row_number() over (order by avg([Profit]) desc) rn_max
    FROM
        Orders
    GROUP BY
        Range_begining
    HAVING COUNT(ID) > 10
)
select [range], [count], [avg profit],
       case when rn_max = 1 
            then 'Max profit'
            else 'Min profit'
        end Description
  from ordering
 where (rn_max = 1 or rn_min = 1)

这里是Sql Fiddle的例子.