CREATE DATABASE LINK "DEV"
CONNECT TO data
IDENTIFIED BY "my_password"
USING '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)
  (Host=dev_server)
  (PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=DEV)))';

create table abc_001_differences as
select a.updated as prod_updated, b.updated as dev_updated
  from abc_001 a
  full outer join abc_001@"DEV" b on a.primary_key = b.primary_key
;