SQL Filter A Set of Records At latest revision

Use CTE to do it, like

with cte as
(select group,product,revision,row_number () over (partition by group order by revision desc) rn
from tab1)
select b.group,b.product,b.revision
from cte a,tab1 b
where rn=1
and a.group=b.group
and a.revision=b.revision;

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Many Thanks & Best Regards, Hua Min