Help! "Show Value As" calculations in Pivot Table Grayed Out

[Rachel Greenberg]

Hi,

I'm trying to do a basic "Show Value As" calculation in my pivot table - I want the column that I'm adding to show as a % of the Grand Total.  However, after I select the "% of Grand Total" option from the drop down in the Value Field Settings window I am unable to select the base field - they are all grayed out:

My source data is within the same excel workbook.  Any help would be greatly appreciated!

[#2]

I have 2 sheets A & B. Sheet A has 3 columns: Store name, Location and no. of products, (50 rows) Sheet B has 3 Columns, Store Name, Location and No. of products (2400 rows), i have values for store name and location in this sheet. Now i want to have value of no. of products in Sheet 2 on condition that combination of store name and location should match in sheet 1 to give me corresponding value. Which formula should i use.