Hello Chris!

ID in skills tables are the foreign keys (I don't really have control over how this was designed) Users_Hierarchy works like this with the other tables:

dbo.users_hierarchy.EMPLOYEEID = new_skills.id

dbo.users_hierarchy.OLDID = old_skills.id

Hope that helps describe what I'm talking about. 🙂

EDIT: A very simplified version of what I'm trying to do is SELECT the difference BETWEEN old_skills AND new_skills using only users_hierarchy's employeeid and oldid WHERE employeeid = new_skills.id AND oldid = old_skills.id