Thank you Lucas,
You are correct on one aspect, that my problem description is not very detailed. I have done the same thing you are proposing in another case by breaking the two columns in to 12 rows. But the issue I will run into is that the source table is a huge ECC controlling table. if I convert flat structure to multiple rows my table volume will multiply be 16. So I was looking not to do that, but achieve the same result with nested if...
The same is just for explanation only. I am talking about COSS and COEP table. where each column is for a period, and depending on the period I should sum up all values up to that period. In these tables no month value available as well. So it is bit challenging, but I have used a case within select to achieve the result, but there is still a challenge.
Even though the method you have given will work it is making the model bit too large and too many nodes. I want it to be achieved thru nested if, if I can as that is simple. I will keep the post open for now.
I do appreciate your effort to help me.
Thank you,
Arthur.