Thanks - you’re quite right about the first one really just needing an inner join - I have amended that one now.
With your change above, that is giving me all the trade_users.
Basically category 19 is ‘country’, so I’m trying to create lists of all the trade users with and without a country, so that someone can keep track of all the ones we have added a country for.
So in plain English terms I’m looking for trade users which have no activities plus trade users with any activities other than those with a Category_ID of 19.
(Excuse the naming convention - obviously countries are not activities. When the project started they were just activities, but location kind of got included - ‘keywords’ would be a better term probably.)