I’d recommend the following steps:
* Click on the base view *bv_product_by_category*, right-click on it and then select New → Selection.
* In the new tab of your VDP Admin go to the *Output* tab and right-click on the parameters field and select *Project subfields of*. This operation transforms your compound field into a simple field, i.e. instead of a register as an output you get a simple field
* After this, remove the *parameters* field by clicking the checkbox left to it and clicking “Remove Selected” on the bottom-right corner
For a better understanding of compound values I recommend you to read [User Manuals / Virtual DataPort VQL Guide / Advanced Characteristics / Management of Compound Values](https://community.denodo.com/docs/html/browse/6.0/vdp/vql/advanced_characteristics/management_of_compound_values/management_of_compound_values)
Hope this helps!