Grab latest weekend in graph

[#1]

I have a date island and a graph that graphs against months. For my equation, the first part is simple:

Sum( if(SalesMonth = Month, SaleAmount, 0))

Next I have a requirement where I need to add a value that is based on the greatest WeekEnd in a month. So each week a value is added for the weekend. Looks like:

DATE WeekEndValue

01/07/2011 1000

01/14/2011 500

01/21/2011 750

01/28/2011 500

02/04/2011 700

02/11/2011 600

So in the graph for Jan i need to grab the 01/21/2011 value and add it to the SalesAmount for that month.

Here's what i've been trying:

Sum( if(SalesMonth = Month, SaleAmount, 0))

+

Sum(if(SaleWeekEnd = weekend(monthend(makedate(Year, Month, 1))), WeekEndValue, 0)

Can't seem to get it to work though. Any ideas? Thanks.

[#2]

anyone? does it not make sense?

[#3]

Hi,

Try Set Analisys:

Sum( {$<SalesMonth = Month>} SaleAmount)

+

Sum({$<SaleWeekEnd = {'$(weekend(monthend(makedate(Year, Month, 1))))'} >} WeekEndValue)

Hope this helps.

Best Regards!