Working with SharePoint Modern and user profiles that have with category fields to populate with topics of interest.
I've set up a search results page for "pages for me" that refines results automatically, based on the value/s the user select/s for their 'business area', 'product' and other (4) categories that they're interested in.
...AND {|Refinablestring123:{User.BusinessArea}} AND {|Refinablestring123:{User.Product}}...etc
This works fine, and returns results whether the user has selected one or a number of values in each category.
The problem arises when the user leaves the category field blank, either because they want to see all topics in that category, or that category is not relevant to them. The search results are empty due to the vacant field.
Is there a way to treat a blank category as "all values"?