Dynamic variable & previous date value

[aisolomatin]

Greetings!

I'm trying to get previous date value via set analysis in straight table.

I get expression/variable for previous date (column 5):

v_prev_m =if(Dimensionality()=0,
        Date(MonthEnd(AddMonths(Min(CurDate),-1))),
        Date(MonthEnd(AddMonths(CurDate,-1))))

Expression for previous month value (column4):

=Sum(
        Aggr(
              Sum({<CurDate={"$(=v_prev_m)"}>}Fact),
              Territory))

Everything works pretty nice if I choose only one date (field 'CurDate').

But if i will choose two or more fields in 'CurDate', then expression works only for first row.

And variable in expression calculate only for first row, although in column 5 it estimates for every row.

Is there any ways to make it right?

So, if somebody could help I really appreciate.

Thanks in advance, Andrey

[Gysbert_Wassenaar]

See this document: Calculating rolling n-period totals, averages or other aggregations