Using LEAD window function in an update and merge

gistfile1.txt

--Oracle Merge
merge into depreciation_rate d
using
(select asset,
        country,
        effective_from,
        lead(effective_from) over (partition by asset, country order by effective_from)  - 1/86400 as effective_until
 from depreciation_rate) n
on (d.asset = n.asset
    and d.country = n.country
    and d.effective_from = n.effective_from)
when matched then
update set d.effective_from = n.effective_from;


--PostgreSQL update
update depreciation_rate d
set effective_until = (select
                          effective_until
                       from (select lead(effective_from) over (partition by asset, country order by effective_from) as effective_until,
                                ROWID as rid
                             from depreciation_rate) a
                       where a.rid = d.ROWID);