SELECT w.id, wp.age, w.coins_needed, w.power
FROM Wands w
JOIN Wands_Property wp ON w.code = wp.code
JOIN (
    SELECT wp.age, MIN(w.coins_needed) AS min_gold, w.power
    FROM Wands w
    JOIN Wands_Property wp ON w.code = wp.code
    WHERE wp.is_evil = 0
    GROUP BY wp.age, w.power
) mc ON wp.age = mc.age 
     AND w.power = mc.power 
     AND w.coins_needed = mc.min_gold
ORDER BY w.power DESC, wp.age DESC;