# Calculating index vs Year Ago

i have a calendar date column and a sales\$ column. i would like to calculate sales index vs year ago. How can i do that within Beast Mode?

Date: Calendar date

Sales \$

e.g:

Sales IYA = (Sales \$ on 15May2020) / (Sales \$ on 15 May 2019) * 100

is there a way i can shift the date to create a (sales \$YA) column?

• Budapest / Portland, OR 🔴

Create a Table of Dates with columns

Report Date , Actual Date , Period Type

1/1/2020 , 1/1/2020, 'Current'

...

then UNION all the dates with the offset

1/1/2020, 1/1/2019, 'Previous Year'

1/2/2020, 1/2/2019, 'Previous Year'

...

then Fusion your lookup table to your transactional data.  (this will effectively double your output rows, so i have one chunk 'Current' and a second chunk 'Previous Year'

Then construct beast modes:

CurrentAmount = sum(case when 'period type' = 'current' then amount end)

PreviousYearAmount = sum(case when 'period type' = 'previous year' then amount end.)

This model is super effective b/c you can easily extend to include previous month, or previous quarter etc.

Jae Wilson
Check out my 🎥 Domo Training YouTube Channel 👨‍💻

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