I am trying to calculate the cummulative monthly sum of a specific value but with the caveat that said value only exists for a particular time window. There will be an associated startDate and an associated endDate for each value. An example data table detailing an example data set is given here:

A table detailing the resulting calculated cummulative sum is given here:

And the resulting plot I would be looking for is given here:

Having reproduced this propblem in Excel. (N.B. that I have used quarters as an example, but I would need the granularity to be monthly).
May I please have advice on how best to accomplish this within Domo. I don't believe that this should be hard but I am really struggling. Would you recomend using the MySQL Magic ETL to create a new data series or can I do this within the analyser window by making use of filters (for example)?
Thank you in advance.
Regards,
Matthew