UPDATE Test_Current_Year D

SET Test_util=C.Test_util+C.full_Variance FROM

(SELECT A.Test_util,B.full_Variance,A.Name FROM  

(SELECT * FROM Test_Current_Year WHERE Month_Number=7) A JOIN

(SELECT * FROM Test_Temp WHERE Month_Number=8) B ON A.Name=B.Name) 

I am working on the forecasting requirement.Assume that the current month is 4 where data will not be available by applying the forecasting logic I should take last year's data into consideration like finding the variance of Apr,Mar of last year and add the variance value to the current year's Mar to fore cast as Apr data for current year..The month number should be adjusted dynamically based on the current month

Example:current month=4(current year)

(lastyear)Apr-Mar=variance

current year Mar+varince(above step)=Apr value(forecast)

current month=5(current year)

(lastyear)May-Apr=variance

current year Apr(got in previous step)+varince(above step)=May value(forecast)

similarly I have to forecast till dec