Query to find size of partition in oracle(it has subpartitions too)

Hi All,

I want to query the size of a particular partition which has got sub partitions too. I am running the following query but not getting any output.

So request to please let me know how can i get the size of a particular partition in oracle.

SQL> SELECT partition_name, bytes/1024/1024 "MB" FROM dba_segments WHERE segment_name = '& TABLE_NAME'  AND segment_type = 'TABLE PARTITION' ;

no rows selected

Regards

Siva