Formula issue - Add value from previous months
I have been working on this formula for quite a while now, I hope you can give me an idea on how to do this. I will explain it as much as I can since I cannot provide a screenshot of the actual report from the client.
I have 2 tables with Line Item and Time Dimension. "Value 1" row has the value, "Identifier" row , and "Target Result" row is the target module.
so the formula is that IF Identifier is greater than 1 then I need to add the values from previous months. In the Target Result row, May 2013 has the value of 50 because the condition should add values from Jan 13 until Apr 13 which results to 50. Same thing with Jun 13 since Identifier is 1 it will add values from Jan 13 to May 13 and so on. It means the formula is moving as the months progress.
I hope you can give me an idea on the approach as to how to do this.