Question

USE [IMTsimulations]
GO

SELECT SUM(CASE WHEN Xa BETWEEN 90 and 130 THEN 1 ELSE 0 end)/SUM(1) AS Xa_PIR2
  FROM [dbo].[Simulations]
  WHERE [dbo].[Simulations].[ExperimentID] IN (
    SELECT [ExperimentID] FROM [dbo].[Parameters] WHERE [SensorError] = 1 AND [ExogDEXCurve] <> 4 AND [ControlRange] = 2
  )
/*GROUP BY Xa_PIR2 WHERE Xa_PIR2 < .6, Xa_PIR2 BETWEEN .6 AND .8, Xa_PIR2 BETWEEN .8 AND 1 

My attempt at the group, obviously doesn't work. */
GO

我知道我可以做一个SELECT FROM PERCENT_IN_RANGE_TABLE，有点像here，但我没有这样的表。我想在飞行中这样做，因为我只会做一次这种特定的分析。

理想情况下，我会在每个“时间范围”组中进行一定比例的实验。我想知道实验的百分比（由ExperimentID唯一标识）的时间范围小于60％，范围内有60-80％的时间百分比，以及范围内80-100％的时间百分比。

Answer 1

首先使用CTE计算数据，然后将其分组到选择

中

WITH calculatedSimulations
AS
(
  SELECT SUM(CASE WHEN Xa BETWEEN 90 and 130 THEN 1 ELSE 0 end)/SUM(1) AS Xa_PIR2
  FROM [dbo].[Simulations]
  WHERE [dbo].[Simulations].[ExperimentID] IN (
    SELECT [ExperimentID] FROM [dbo].[Parameters] WHERE [SensorError] = 1 AND [ExogDEXCurve] <> 4 AND [ControlRange] = 2
  )
)
SELECT Xa_PIR2, 
       COUNT(*) as count -- for example!
FROM calculatedSimulations
GROUP BY 
   CASE WHEN Xa_PIR2 < 0.6 THEN 1
   CASE WHEN Xa_PIR2 >= 0.6 AND Xa_PIR2 < 0.8 THEN 2
   CASE WHEN Xa_PIR2 >= 0.8 THEN 3
END

Answer 2

您是否尝试按案例陈述进行分组？

SELECT (CASE WHEN Xa_PIR2 < 0.6 THEN 'GROUP1'
             WHEN Xa_PIR2 < 0.8 THEN 'GROUP2'
             WHEN Xa_PIR2 < 1 THEN 'GROUP3'
        END) as grp, COUNT(*) as num, AVG(Xa_PIR2) as avg_in_group
FROM (SELECT AVG(CASE WHEN s.Xa BETWEEN 90 and 130 THEN 1.0 ELSE 0 end) AS Xa_PIR2
      FROM [dbo].[Simulations] s
      WHERE s.[ExperimentID] IN 
                (SELECT p.[ExperimentID]
                 FROM [dbo].[Parameters] p
                 WHERE p.[SensorError] = 1 AND p.[ExogDEXCurve] <> 4 AND p.[ControlRange] = 2
               )
     ) s
GROUP BY (CASE WHEN Xa_PIR2 < 0.6 THEN 'GROUP1'
               WHEN Xa_PIR2 < 0.8 THEN 'GROUP2'
               WHEN Xa_PIR2 < 1 THEN 'GROUP3'
          END);

有关查询的一些注释：

AVG()是一个聚合函数。你不需要做两笔钱，除非你真的非常想要。
CASE语句按顺序处理条件，因此您无需使用BETWEEN。
我总是在小数点前加上“0”，以防止无意的错误或误读查询。
包括该组的平均值可以增强有关值分布的信息。
表别名是个好主意。

Answer 3

试试这种事。

select this, sum(that) sumOfThat
from (
select case when whatever then 'fred' else 'barney' end this
, case when whatever then 0 else 1 end that
) temp
group by this

如何根据我在查询中计算的内容的范围进行分组？

3 个答案: