Comparative, Cumulative order by week, resetting at year end

[GSmith]

Hi,

Just started with Qlik, I'm trying to create a bar chart comparing cumulative orders by week in the last 3 years.

It needs to reset the count on the last day or first day of the year

The date range and comparison I have sorted out already.

The problem I have is getting the cumulative count to work properly.

it needs to give a distinct count of customers - so once they have placed an order in (for example) week 1, they should not be counted in any of the later weeks. But this should reset in Week 1.

This is where I have got to so far:

=if(Week(Date)=1,0,

RangeSum(Above(TOTAL count({<year,month,week, DateField = {"<$(=maxstring(DateField))"},DateType={[Cust.]}> } distinct [Cust.] ), 0, RowNo(TOTAL)))

)

Any advice would be appreciated, thanks - I fully expect I'm quite a way out here!