Du kan använda rang över partition så här:
select * from
(select locid, value1, value1date,
rank() over (partition by locid order by value1date desc) as rank
from table1) t
where t.rank=1
Se SqlFiddle
Du kan använda rang över partition så här:
select * from
(select locid, value1, value1date,
rank() over (partition by locid order by value1date desc) as rank
from table1) t
where t.rank=1
Se SqlFiddle