Calculating Quarterly average from monthly data

SELECT SUM(UrColumn) Total, DATENAME (qq, urDAteColumn ) as Quarter
FROM urTable
GROUP BY DATENAME (qq, urDAteColumn )

How do you identify month in your data? Is a date or string?

As the rough estimation you may use following (suppose monthNr is numeric month number 1 - 12, YearNr is four digits Year number):

SELECT cast((monthNr-1)/3 AS int)+1 Quarter, YearNr, AVG(monthlyValue)
  FROM YourTable
 GROUP BY cast((monthNr-1)/3 AS int), YearNr

SELECT cast((monthNr-1)/6 AS int)+1 HalfNr, YearNr, AVG(monthlyValue)
  FROM YourTable
 GROUP BY cast((monthNr-1)/6 AS int), YearNr

The above solution is returning just 4 rows of data.
I have 10 years of monthly data(120 rows).
 That means it should return 30 rows.
Any better solution ???

The SP creation is also easy but you have to know how it should store/return results. If you just need above SELECTs in SP execute the following code (updated to your structures). You may create input parameters for date range in this SP etc.

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
 
CREATE PROCEDURE sp_quarterlyData 
 
AS
BEGIN
SET NOCOUNT ON;
 
SELECT cast((monthNr-1)/3 AS int)+1 Quarter, YearNr, AVG(monthlyValue)
  FROM YourTable
 GROUP BY cast((monthNr-1)/3 AS int), YearNr
 
END
GO

Select allOpen in new window

SELECT SUM(UrColumn) Total, DATENAME (qq, urDAteColumn ) as Quarter , YEAR (urDateColumn ) as [Year]
FROM urTable
GROUP BY DATENAME (qq, urDAteColumn ) ,YEAR (urDateColumn )

My solution does not return just 4 rows.If you have date column then you may update it:

SELECT Datepart(qq, YourDate) Quarter, DatePart(yy, YourDate) YearNr, AVG(monthlyValue)
  FROM YourTable
 GROUP BY Datepart(qq, YourDate), DatePart(yy, YourDate)

The more accurate way would be to calculate half year and quarterly data from daily data because it reflects number of business days.

Hi guys

Thank You very much for your Immediate response.
I am overwhelmed.
I am getting Quarterly averages for all the indexes.
But my table has 2 indexes one is Dow and second one is S&P.
how to get different avarages for these 2 separately

The groupping will remain unchanged, you just have to add one more column for S&P average calculation:

SELECT Datepart(qq, YourDate) Quarter, DatePart(yy, YourDate) YearNr, AVG(monthlyDOWValue) DOWavg, AVG(monthlySaPValue) SaPavg
  FROM YourTable
 GROUP BY Datepart(qq, YourDate), DatePart(yy, YourDate)

BTW, why you are not interested in NASDAQ?