I have a table that uses a Date field as its primary key. Each date in use happens to be a Monday and there are records for every single Monday for the past 6+ years. This means that for a given row, the row below it is always 7 days before it.
Each row also has a Number field that grows from zero (6 years ago) to 7500 (today), but the growth is nonlinear and varies from week to week.
What I want to do is compute a weekly growth rate field. This field would be equal to:
(Number today - Number last week) / Number last week
In order to do this, I need to reference the number field from one week ago. I’m able to compute the date that I should be looking up, but the result is a formula field and I can’t figure out then how to look up the value I need from the appropriate row.