Hi @Diego -
You can use this approach. You can consolidate some of the calcs if needed but I like to go step by step.
1. Create a calculated field that truncates the date to month
c_month
truncdate("MM",{Order Date})
2. Create a calculated field that retrieves the last month (After Filter).
c_last_month
maxOver({c_month},[],PRE_AGG)
3. Create a calculated field that sums only the measure values in the last month.
c_last_month_sales
sumOver(ifelse({c_month}={c_last_month},Sales,0),[],PRE_AGG)
Result:
