You cannot grant privileges DML and select directly to a single partition of a partitioned table.
Why not? (https://docs.oracle.com/database/121/SQLRF/statements_9013.htm#SQLRF01603)
sometimes i have wanted to grant select on a table partition (p2014) but not in the rest of table,
grant select on earnings partition (p2014);
i can see one possible problem here, what happen with" select * from earnings"
if you only have select on partition (p2014) ?
I think that workarround for this it is use VPD, but probably use VPD has a performance leak.
Regards