Percentages of total in Reeport Studio

[cog8user]

Hi,

Suppose I have columns like Product line, Product type, and Quantity.
Product line is grouped and Quantity is not aggregated.
I want to have a new column (Query calculation) showing each Product type's percentage contribution to total Quantity.
How can I achieve this?  ::)

[Suraj]

by creating a data item.
logic such as:
total(quantity for product type)/total quantity overall.