Indirect Set Analysis on Rolling Period

[cicciput]

I cannot understand what's happening here, I wonder if some expert can shine a light on this thing.

I want to compare buyers of a quarter VS the previous one.

To get there I'm using Indirect Set Analysis with 2 AsOfMonth.Type: RQ (Rolling Quarter) and PRQ (Previuos Rolling Quarter)

With no selections this expression returns no results or always 0:

Sum({$< Account.ID =

  p({$< AsOfMonth.Type = {'PRQ'} >} Account.ID) -

  p({$< AsOfMonth.Type = {'RQ'} >} Account.ID) >}

Account.DCF)

while it works if I select a single month:

Here are the LOAD statements for who's willing to help me understand, thanks in advance for your support.

Account:

LOAD * INLINE [

    Account.ID, Account.Name, Account.DCF

    1, Company A, 1

    2, Company B, 1

    3, Company C, 1

];

Purchase:

LOAD * INLINE [

    Account.ID, Date

    1, 27/02/2015

    2, 20/02/2015

    2, 20/11/2014

    3, 10/10/2014

];

Cal:

LOAD

  TempDate AS Date,

  MonthName(TempDate) AS Cal.MonthName;

LOAD

  Date(mindate + IterNo()) AS TempDate

WHILE mindate + IterNo() <= maxdate;

LOAD

  Min(Date) -1 AS mindate,

  Max(Date) AS maxdate

RESIDENT Purchase;

AsOfMonth:

LOAD Cal.MonthName AS AsOfMonth.MonthName,

    MonthName(AddMonths(Cal.MonthName, 1 - IterNo())) AS Cal.MonthName,

    IF(IterNo() < 4, 'RQ', 'PRQ') AS AsOfMonth.Type

RESIDENT Cal

WHILE IterNo() <= 6;

[sunny_talwar]

So its working now? I was working on it right now and was not sure how I would do it. I am glad that you have figured it out.

[cicciput]

Yes, I'm asked to work on a monthly basis so on the real app I'll need to round it up but the concept is working.

Thanks for helping me to understand Set Analysis could not work in this situation.

[sunny_talwar]

Not a problem my friend. I am glad I was able to guide you in the right direction.