Hi,
I think this should be an easy solution, and maybe i am trying too hard
Consider the module below, data coming from a list start date, end date, and a count (1 = yes, 0 = no)

I want to populate Previous YN with a 1 IF the promo count was 1 for the previous period.
So in the example above #2: 31/01/2018 to 28/02/2018 was a promo period, so the promo count =1
Therefore the period starting the #3: 28/02/2018 should show a 1 because the previous period promo count was 1.
The period from #4: 31/03/2018 however should show 0 because the previous period promo count was 0.
I put the expected result in manually in the previous YN column.
thanks
Kev