Like in the title, I am trying to get the last_value of a field for the Return On Investment calculation. Normally, I can do this in Lens Formula (rf. below) on a monthly index. But I don't know how for a daily index.
ROI = sum(*sessions*) / last_value(*subscription_fee*)
So the idea is to get the last subscription_fee, I've been trying to play around with @timestamp field but no hope.