DB2 Aggregate Sum Max Min Over Partition By

 select * from (
  select organisation_code
   ,ref_correlation_id
   ,batch_received_batch_id
   ,event_rr_id
   ,EVENT_RR_LOCAL_REF_ID
   ,EVENT_OPERATION_ID
   ,EVENT_RR_TRANS_TS
   ,max(EVENT_RR_TRANS_TS)
    over (partition by organisation_code, EVENT_RR_LOCAL_REF_ID) as maxTS
  from NPF.npf_event_referral_received
   where organisation_code in ('G00037-F', 'G00035-B')
    and EVENT_OPERATION_ID <> 3
  ) RR
 where EVENT_RR_TRANS_TS = maxTS