Test if click count is missing by checking stories_id, not click_count
Test if click count is missing by checking stories_id, not click_count

That way the query planner doesn't have to access the actual row being
tested and can confine itself to the index only (if it chooses to do so).

berkmancenter/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud