> hello again.
> Forgot to mention, I realise I can check for null specifically and
> get the result I need but I'm mainly curious to know why null
> doesn't appear to be matched in the original "where".

Hi,
NULL means unknown. Records containing NULL in the field in question
are not returned when using e.g.
WHERE Field1 <> 'ABC'
simply because the unknown may or may not be 'ABC'. I do not know
which languages most people on this list speak, and if asked to name
all people who does not speak Italian, I could probably only mention
myself - simply because my knowledge about language skills amongst the
rest of you would be in a NULL state.

HTH,
Set