I noticed that a userid is required to run a query; but what if I want to check out a property for all users? For example, if I wanted to find the sum of upvotes for each user, not just myself? Can I do that?
Sure. Assuming you know a bit of SQL, you can do this quite easily. For instance, this query will select the ten users who've cast the most up-votes:
select Top 10 Id as [User Link], UpVotes from Users Order By UpVotes desc