TSQL 选择最小和分组时的最大行数 [英] TSQL Select Min & Max row when grouping

问题描述

假设我有一个包含许多行的表，如下所示:

Lets say I have a table containing many many rows like this:

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
 ...

我正在做一个这样的简单查询:

I'm doing a simple query like this:

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:

After this query is run I get results like this:

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

很简单:)

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

What I need to do now is to select row with minimum and maximum profit where count is bigger than 10 (this is a parameter)

我能够通过这个获得最小值:

I was able to get minimum value with this:

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

我正在考虑使用 ORDER BY DESC 为上述查询执行 UNION，但这不是最佳解决方案.

I was thinking of doing an UNION for above query with ORDER BY DESC, but it isn't the best solution.

我需要做的:
选择 2 行:按范围分组时，第一行具有最小值，第二行具有最大 AVG Profit.

如果我像这样在主数据表中添加 2 个移动列:

If I add 2 move columns to my main data table like this:

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 2 个这样的条件:

And then try to add 2 more conditions like this:

; 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)

我收到一个错误，因为 [Company] 和 [OrderDate]

I get an error because [Company] and [OrderDate]

在 HAVING 子句中无效，因为它不包含在任何一个聚合函数或 GROUP BY 子句.

is invalid in the HAVING clause because it is not contained in either an aggregate function or the GROUP BY clause.

我该如何解决这个问题?

How can I fix this?

EDIT2成功了！

; 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我可以返回带有这样描述的另一列吗:

EDIT 3 Can I return another column with description like this:

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@Nikola Markovinović 的回答):

EDIT 4 Fast answer (based on @Nikola Markovinović answer):

; 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)

推荐答案

您可以使用 立即完成窗口函数:

; 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 示例.

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