I have data for forecasting, in which every month client is doing forecasting for 2 years, and on the same month they are giving a number called PlaningVersion (Example if Planing is done in Feb 2016, then version no will be 602 (Year last digit + 2 digit of current month))
So I need to calculate Lag3 for my data,
so suppose if I am calculating Lag3 for Dec2017, means its planning version would be 712, so it will sum data for Nov2017+Oct2017+Sep2017 for Planing version 709, means 3 months back (version 709) whatever planning was done for Nov, Oct, Sep will be the Lag3 for Dec2017 (version 712)
Hope I have explained correctly, But this thing I need to do at script level,
I am sorry i am not able to understand. Is doing group by clause on version to get sum of forcast is correct logic, after that we can do sum of previous three months.
