从多个表中的多个列中获取唯一值的完整列表

Back story if you want it: I have an odd situation. An organization affiliated with my own provides us with a database that we use heavily; a few other organizations also use it, but our records are easily more than 90% of the total. We have a web frontend for data entry that is connected to the live database, but we only get the backend data as an Access file of selected tables that are sent to us periodically. I have an odd situat