TrentB Member

still looking for a solution here

that is correct. month(`Invoice date`) returns the month number

Invoice date field is a date field not text or numeric and looks like "2018-Jan"

the data set includes a row for each account invoice. invoice dateaccountamountJanA $ 100JanB $ 50JanC $ 200FebA $ 150FebB $ 25FebC $ 200FebD $ 125MarA $ 150MarC $ 175MarD $ 150AprA $ 200AprC $ 225AprD $ 200AprE $ 150