Oracle 18c

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with src_nodes as (

select 1 id, 'A' nvalue, date '2021-01-01' vfrom, date '2021-02-10' vto

from dual

union all

select 1, 'B', date '2021-02-15', date '2021-02-28'

from dual

union all

select 2, 'C', date '2021-01-01', date '2021-01-31'

from dual

union all

select 2, 'D', date '2021-02-01', date '2021-02-28'

from dual

union all

select 3, 'E', date '2021-01-01', date '2021-02-28'

from dual

union all

select 4, 'F', date '2021-01-01', date '2021-01-31'

from dual

union all

select 4, 'G', date '2021-02-01', date '2021-02-28'

from dual

union all

select 5, 'H', date '2021-02-01', date '2021-02-28'

from dual

union all

select 6, 'I', date '2021-02-10', date '2021-02-28'

from dual

src_links as (

select 1 link_child, 2 link_parent

from dual

union all

select 2, 3

from dual

union all