How to compare field values from this year vs last year by date and calculate the percentage change?

Hi, I have data in 2 fields in table: one is date and the other is some value, for each year respectively. Now I want to perform an action like compare date_1 from 2015 vs date_1 from 2016, then perform some evals on the data. For example: 01-01-2015 1234567 02-01-2015 1234578 01-01-2016 1234563 02-01-2016 1234577 Now I want to compare 01-01-2015 with 01-01-2016, see if they are equal greater less, and do a percentage change based on the data. Please recommend I have pulled all the dates using stats values by date and appended by a similar fashion for each year by adding the where clause in the date range.