Force month of a complex variable

[#1]

Hello,

I would first like to congratulate you for the splendid forum and professionalism.

I have a complex variable, with sums and if inside, I wanted to know how to force the date since this classic with set analysis is not taken,

For example:

Variable:

$v_sales = if ((cal_yyyy) = Year (Today ()) -1, sum($(sales_ytd), count($(sales_y))

/

if ((cal_yyyy) = Year (Today ()) -1, count ($(contra_ytd), count($(contra_y))

Set Analysis:

= sum( {< Month={'JAN'} >} $v_Sales)

in this example, when I select a month I only ever returns the sum of the month, if you select more months, the sum is accumulated,

what I want is to set the sum to one month of the variable,possibly ignoring other selections or more selections.

Thank you very much, and I apologize for my bad English.