Need to create an expression that uses values from same column

[Brenna Heinrich]

Hello, I need to create a specific calculation to generate a new data field called BOE. The data is structured into four columns: Field, Month, Product, Volume. I need to add together the volumes of thetwo products(Oil & Gas) and divide by 6 to get BOE, per Month. What syntax would I use in order to achieve this calculation

[Gaia Paolini]

I am assuming there is one entry for Oil and one for Gas every Month.

So something like this

Sum([Volume]) over (Intersect([Month],[Field])) / 6

if not, please can you upload a test dataset.