How to select latest entries for each raw_id?

Question

PostgreSQL

There is a table with records of this kind

How can I elegantly get the last single_sum for each raw_id in one query. so

far, nothing better than this has come up

select
    id,
    raw_id,
    single_sum
from
    my_table
where
    id in (
        select
            max(id)
  from
            my_table
        group by
            raw_id)

Answer 1

select distinct on (raw_id) raw_id, id, single_sum 
from tablename
order by raw_id, id desc

Maybe I mixed up the sort direction as usual.