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with units(org_id, title, unit_valid_from, unit_valid_to, origin) as (
select 101, 'T101A', date '2019-05-14', date '2019-05-17', 'different' from dual union all
select 101, 'T101B', date '2019-05-15', date '2019-05-17', 'history' from dual union all
select 101, 'T101C', date '2019-05-16', date '2019-05-17', 'current' from dual union all
select 201, 'T201A', date '2019-05-14', date '2019-05-17', 'different' from dual union all
select 201, 'T201B', date '2019-05-15', date '2019-05-17', 'history' from dual union all
select 301, 'T301A', date '2019-05-14', date '2019-05-17', 'different' from dual union all
select 301, 'T301B', date '2019-05-15', date '2019-05-17', 'different' from dual )
select units.*,
case when 1 =
row_number() over (
partition by org_id
order by case origin when 'current' then 1 when 'history' then 2 else 3 end,
unit_valid_from ) then 1 else 0 end as is_correct_version
from units
