Question : sql - date format

I used to have oracle 9 i. I think it is now oracle 10 g and I have a sql that used to run fine, but is now throwing this error:
where alian_join_dt >= trunc(sysdate)-10101010101010101010
                                     *
ERROR at line 3:
ORA-01841: (full) year must be between -4713 and +9999, and not be 0

----my sql is :
select acct_nbr, type
from mytable where join_dt >= trunc(sysdate)-1;

Answer : sql - date format

There is nothing wrong with:
select acct_nbr, type
from mytable where join_dt >= trunc(sysdate)-1;


What is generating:
trunc(sysdate)-10101010101010101010


This will fail since it trying to subtract 10101010101010101010 days from sysdate.