SQL & PL/SQL

Hi all,
I have a huge partitioned table with 117 million rows. The table is partitioned into 3 partitions. My problem is that I cannot select row counts from 2 of the partitions. The other partition does return a result.
On the two partitions for which I get no result, no error is being returned, the query just doesn't do anything.
The syntax I am using is the same in all cases.

Select count(1) from cmf partition (p1);

cmf - table name
p1 - partition name

there are 3 partitions p1, p2 and pcurrent - I can select from p2 but not from p1 and pcurrent.

also can i use hints when selecting from a partition as shown below:

select /*+ FULL PARALLEL(cmf,32)*/ count(1) from cmf partition (P1)

Thanks.