How to get mean ,median , mode and range in a single select query?

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死守一世寂寞
死守一世寂寞 2021-01-27 09:06

I\'m trying to get mean, median, mode and range for a set of values in a table. I was able to get the average but median, range and mode I\'m getting a wrong one.

Below

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  •  夕颜
    夕颜 (楼主)
    2021-01-27 09:51

    Not sure if this will help, but here is some sql which allows me generate some stats (..., mean, median, mode,..) within a group by

    • cteBase would be your core data (non-aggregated or groupded)
    • cteMedian would generate the median of cteBase
    • cteMode would calculate the mode of cteBase

    I am calculated only one measure, but I suspect it can easily be expanded Where I have "GrpByYear", this would have to be expanded into your compound fields.

    ;with cteBase as (
         Select RowNr=Row_Number() over (Partition By Year(TR_Date) Order By Year(TR_Date),TR_Y10)
               ,GrpByYear = Year(TR_Date)
               ,Measure = TR_Y10
         From [Chinrus-Series].[dbo].[DS_Treasury_Rates]
         Where Year(TR_Date)>2014
        )
        ,cteMedian as (Select A.GrpByYear,Measure From cteBase A Join (Select GrpByYear,RowNr=Max(RowNr)/2 from cteBase Group by GrpByYear) B on (A.GrpByYear=B.GrpByYear and A.RowNr=B.RowNr))
        ,cteMode   as (Select * from (Select RowNr=Row_Number() over (Partition By GrpByYear Order by Count(*) Desc),GrpByYear,Measure,Hits=count(*) From cteBase Group by GrpByYear,Measure) A Where RowNr=1)
        Select A.GrpByYear
              ,RecordCount   = Count(*)
              ,DistinctCount = Count(Distinct A.Measure)
              ,SumTotal      = Sum(A.Measure)
              ,Minimum       = Min(A.Measure)
              ,Maximum       = Max(A.Measure)
              ,Mean          = Avg(A.Measure)
              ,Median        = Max(B.Measure)
              ,Mode          = Max(C.Measure)
              ,StdDev        = STDEV(A.Measure)
         From cteBase A
         Join cteMedian B on A.GrpByYear=B.GrpByYear
         Join cteMode   C on A.GrpByYear=C.GrpByYear
         Group By A.GrpByYear
         Order By A.GrpByYear
    
    
    Year    RecordCount DistinctCount   SumTotal    Minimum Maximum Mean    Median  Mode    StdDev
    2016    110         43              204.82      1.63    2.25    1.862   1.84    1.83    0.128568690811108
    2015    251         69              536.71      1.68    2.50    2.1382  2.16    2.20    0.1662836533952
    

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