I would project a field in Virtual DataPort Administration tool by following the below steps,
* Right-click on the base view “bv_product_by_category” and select New > Selection to create a Selection view.
* Under the “output” tab of the new_view, rename the view name as “dv_product_by_category_simple”
* Then, right-click on the “parameters” field under the Field Name column and choose “Project subfields of ‘parameters', rename the categoryname as input.
For more information, you can also refer to the similar community question [Denodo Training - Derived Views](https://community.denodo.com/answers/question/details?questionId=9060g00000009rRAAQ&title=Denodo+Training+-+Derived+Views).
Hope this helps!