I've built a custom report to remove some categories from a Webfilter report. Ideally, I'd like to select a few categories for which to gather reports, but when I create the SQL query, I can only select the field, the operator, and a specific category. In SQL I'd do a WHERE query similar to `WHERE category IN (category1, category2)` etc, but the GUI doesn't let me select more than one category.

Also, the default way to combine WHERE clauses seems to be AND, so I need to pick each category I don't want and say `WHERE category IS NOT category1`. That's not super convenient.

So, how can I do a proper WHERE IN clause?