Window function to calculate average in SQL Server 2008 R2

Question

I don't have much experience with window functions and I have to use one for my average calculation, This is my code:

    AVG(b.TotalSilkHrs) OVER(partition BY b.TECHNICIANCODE
    ORDER BY b.rankID 
    ROWS BETWEEN CURRENT ROW and 3 FOLLOWING) AS MovingAvg

I calculate average of sum that was calculated in subquery. It gives me error :

Msg 102, Level 15, State 1, Line 24 Incorrect syntax near 'ROWS'.

Why am I getting error? I used the code I got from your site

Answer 1

Your original syntax works only for SQL Server 2012, for older versions Try this

;WITH AVGCTE AS
(
     SELECT *, 
     ROW_NUMBER() OVER(partition BY TECHNICIANCODE ORDER BY rankID) Rn 
     FROM TableA
)

SELECT A.*, B.AVG_COL
FROM AVGCTE A
CROSS APPLY 
(
   SELECT x.AVG(TotalSilkHrs) AVG_COL 
   FROM AVGCTE x WHERE x.Rn BETWEEN A.rn and a.rn + 2  
   AND  A.TECHNICIANCODE  = x.TECHNICIANCODE        
) B