Hi,
I see your book chapter on customizing the crosstab column groupings and can see how to change it to also allow monthly groupings. But I can't see how to extend further to weeks. I'd like to display the first date of the week in the column.
To be honest, it looks like the formula sets the column names but I don't see how that affects the grouping itself as well.
John
p.s. looking forward to the new book - I bought the .NET programming book just to have a physical reference.