Thanks Chuck, I thought it would be doable, just didn't know how to write the query.
Another question, can you tell me what's wrong with this query?
Content visible to verified customers only.
It breaks here and I'm not sure why. I'm having a hard time finding references that explain how to formulate queries.
I'm trying to return all keywords from all photos from certain categories that I specify. Later I might write it so that the array of categories is found by looking at the categories table to find children of a parent category, so I can say I want all keywords from a certain category and any children.