Finding person with most medals in Olympics database
This alternative to @rolfl's answer is more readable, in my opinion.  It also has a more efficient execution plan.

WITH medal_count AS (
    SELECT athlete
         , SUM(total_medals) AS grand_total_medals
         , RANK() OVER (ORDER BY SUM(total_medals) DESC) AS rank
        FROM Olympics
        GROUP BY athlete
)
SELECT athlete
     , grand_total_medals
    FROM medal_count
    WHERE rank = 1
    ORDER BY athlete;


SQLFiddle