How to handle users who have earned no points within a period

[JDGrimes]

Something that we'll have to decide is how to handle users who have not earned any points in a given period.

In the wordpoints_points_get_top_users() function in core, we query the users table with a LEFT JOIN on the usermeta table. Essentially, we include the users with no points in the list of top users. This is partly because of complaints about the table being empty, or not showing some users. Or really, I guess it was about the table showing less than the number of requested users. But the reason for that was because the site did not have very many users with points yet.

Showing the non-earners in the table makes the query more expensive, and it really has little value, as far as I can tell, so I'm leaning against it. Instead, I'd suggest that we add a row that contains a message that there were no more points earners within the period, or something to that effect.