Oracle om maximale record op te halen

U kunt een subquery gebruiken die de max(process_date) . krijgt :

select c1.b_id,
  c2.MaxDate
from table_a a
inner join table_b b
  on a.a_id = b.a_id
inner join table_c c1
  on b.b_id = c1.b_id
inner join
(
  select max(process_date) MaxDate
  from table_c
) c2
  on c1.process_date = c2.maxdate;

Zie SQL Fiddle met demo

Of u kunt row_number() . gebruiken :

select b_id, process_date
from 
(
  select c1.b_id,
    c1.process_date,
    row_number() over(partition by a.a_id order by c1.process_date desc) rn
  from table_a a
  inner join table_b b
    on a.a_id = b.a_id
  inner join table_c c1
    on b.b_id = c1.b_id
) 
where rn = 1

Zie SQL Fiddle met demo