Show data in pivot table as null or 0 based on calendar month/year in column heading
I am working on creating a report for forecasting purposes. My report is a pivot report with columns of monthly data, starting with Jan 2008 through July 2010 and rows of product/color/size data. For dates (columns) where products were not shipped, I want to show - or blank. For dates where products were shipped, but no sales reported, I want to show 0. I need to compare a date field (firstshipdate) to the pivot table column heading of month/year (Jan08 through Jul10). Please Advise. Thanks.