BUG #16216: the result of to_date function with negative year number not same as BC year number - Mailing list pgsql-bugs

The following bug has been logged on the website:

Bug reference:      16216
Logged by:          zhongxuan sun
Email address:      szx9231@gmail.com
PostgreSQL version: 12.0
Operating system:   centos7
Description:

example:
postgres=# select to_date('-120', 'yyyy');
    to_date    
---------------
 0121-01-01 BC
(1 row)

postgres=# select to_date('120bc', 'yyyybc'); 
    to_date    
---------------
 0120-01-01 BC
(1 row)

I think -120 means 120bc, however, the output is 121bc not 120bc.

Thanks~