Bug / Unexpected behaviour of NOT LIKE

Hi,

I believe that I have found a bug or at least an undocumented unexpected
behaviour in the NOT LIKE operator (tested in PG 13). Namely, the query

SELECT * FROM users WHERE comment NOT LIKE 'hello%';

*never returns any users where the comment cell is empty, even though empty
also isn't "hello%".* This caused bugs in several parts of my code and
there is nothing about it in the documentation of the LIKE operator.

If this is intended behaviour, I believe that it deserves a big warning
note in the documentation: all occasions where someone might reasonably use
NOT LIKE should be combined with a IS NULL OR, i.e. "comment IS NULL OR
comment NOT LIKE 'hello%'"

Best wishes,

Judith Meyer
>>DiEM25