Average of current month variable and previous month

[#1]

I'm new to QlikView and am struggling to write a formula for the following scenario:

- The average of a variable (vLodgements) for the current month and the previous month, when only the current month is selected.

Does anyone know what I should be using? This is what I have at the moment & it's not working:

if(count(DISTINCT [Fin Period]) = 1, (sum({$ <[Fin Period] = {"<=$(vMaxFinPeriodComp)"} - {"<$(vMinFinPeriodComp)"},[Fin Year]=,[Fin Month]=, [Fin Week]=>}$(vLodgements)

[lironbaram]

hi i would suggest to include in your calendar table

a MonthYear field who will hold the first date of the month as value , you can create it using the monthstart function

then your function shuld look like

f(count(DISTINCT [Fin Period]) = 1, (avg({$ <[Fin MonthYear] = {">=$(=addmonths(max([Fin MonthYear] ),-1))"} ,[Fin Year]=,[Fin Month]=, [Fin Week]=>}$(vLodgements)

[#3]

Thank you.

Do I need to add this into the calendar script? Can you give me an example of how I would do this? I'm not familiar with the Month Start function.

Thanks again.

[lironbaram]

let say your calendar script looks like:

load date,

          year(Date) as Fin Year,

  .....

then you just add new line

         monthstart(Date) As Fin MonthYear

very simple