select wands.id, t.age, t.coins_needed, wands.power
from wands
inner join (
    select wands.code, power, min(coins_needed) as coins_needed, min(age) as age
    from wands
    inner join wands_property 
        on wands_property.code = wands.code 
            and wands_property.is_evil = 0
    group by wands.code, wands.power
) as t 
    on t.code = wands.code 
        and t.power = wands.power 
        and wands.coins_needed = t.coins_needed
order by wands.power desc, t.age desc