Oracle: DBA_TAB_SUBPARTITIONS

create table tq84_part_intv_rng (
   num    number,
   grp    varchar2(1),
   val    number
)
partition by range (num) interval (100)
   subpartition by list (grp)
        subpartition template (
          subpartition sub_part_a values ('A'),
          subpartition sub_part_b values ('B'),
          subpartition sub_part_c values ('C')
        )
(
   partition values less than ( 100 ) 
);


insert into tq84_part_intv_rng values (888, 'B', 42);
insert into tq84_part_intv_rng values (333, 'C', 99);

select
   prt.high_value             prt_hv,
   sub.high_value             sub_hv,
   prt.partition_position     prt_pos,
   sub.subpartition_position  sub_pos,
   sub.subpartition_name,
   sub.partition_name,
   prt.subpartition_count,
   prt.composite
from
   user_tab_subpartitions sub                                               join
   user_tab_partitions    prt on sub.partition_name = prt.partition_name and
                                 sub.table_name     = prt.table_name
where
   sub.table_name = 'TQ84_PART_INTV_RNG';