I'm wondering if something like this can be done in mysql...

I have two tables I want to pull data from. One table will contain a
unique user_id which I could pull out like:

select user_id from table;

that's basically all I would need from that table. The second table
contains a user id field, but can have several duplicate user_id's in
the table. Essentially I would need:

select distinct user_id from table2 where user_id != owner_id;

Then between the results of the two queries, I would like to remove any
duplicate user_id's. I can do this easy enough in PHP, but I would
prefer to increase my mysql skills. Is it possible to somehow combine
these two queries into one and pull out the uniques using distinct?

Thanks in advance!