Trying to create date based interval partition and running into ORA-01858

Hi -

I am trying to create interval based partition but running into this issue:

ORA-01858: a non-numeric character was found where a numeric was expected

eg.,

SQL> create table test1

  2  (id number(3), joindate date)

  3  partition by range (joindate) interval(NUMTOYMINTERVAL(1, 'MONTH'))  (partition p0 values less than ('sysdate-1'));

create table test1

*

ERROR at line 1:

ORA-01858: a non-numeric character was found where a numeric was expected

Does anyone have a way to overcome this?