Question about formula editor

Hi just started to check out Zoho, and maybe I am missing something but how can I create a 'percent growth' formula that does else but calculate the percentage change when comparing a specific FIELD VARIABLE X with the value of X in the previous record (after records have been sorted accordingly via grouping them on Date)? I.e. let's say if we have the following 2 records 1 Value1 2 Value2 etc I do now want to add a new variable GROWTH as (Value2/Value1)-1 Obviously it will lead to a missing value for the first variable since there is no Value0. But it should be no problem for later variables. It is an easy thing in Excel but cannot seem to find its solution here.