As clarified in your comment, Spacemoses, you stated an example: WHERE (Note is null) ^ (ID is null). I do not see why you chose to accept any answer given here as answering that. If i needed an xor for that, i think i'd have to use the AND/OR equivalent logic:
WHERE (Note is null and ID is not null) OR (Note is not null and ID is null)
That is equivalent to:
WHERE (Note is null) XOR (ID is null)
when 'XOR' is not available.