fdh.distribution_id  fdh.locaton_id fd.ytd_deprn  fd.deprn_amount

select fdh.distribution_id, fdh.location_id, fd.ytd_deprn, fd.deprn_amount
from (select row_number() over (partition by dist.book_type_code,dist.asset_id 
                                order by dist.date_effective desc) rn
      ,      dist.book_type_code
      ,      dist.asset_id
      ,      dist.distribution_id
      ,      dist.location_id
      from   fa_distribution_history dist) fdh
,    (select row_number() over (partition by dd.asset_id, dd.book_type_code 
                                order by period_counter desc) rn
      ,      ytd_deprn
      ,      deprn_amount
      ,      asset_id
      ,      book_type_code
      ,      distribution_id
      from   fa_deprn_detail dd) fd
where fd.distribution_id = fdh.distribution_id
and   fd.book_type_code = fdh.book_type_code -- Not required, after the join on distribution_id
and   fd.asset_id = fdh.asset_id             -- But it allows the optimizer a better cardinality estimate.
and   fdh.rn=1
and   fd.rn=1;