List each donator name and the amount of endowment in descending order of the amount of endorsement.
select donator_name, sum ( amount ) from endowment group by donator_name order by sum ( amount ) desc
which donator has the highest amount of endowment?
select donator_name, sum ( amount ) from endowment group by donator_name order by sum ( amount ) desc limit 1
which donator has the lowest endowment amount?
select donator_name, sum ( amount ) from endowment group by donator_name order by sum ( amount ) asc limit 1