> > Actually I am not sure whether the column = NULL syntax is even defined
> > or allowed in SQL92 (e.g. Informix interprets the NULL as column name in
> > this context and errs out).
>
> I don't have the standard handy, but I do have Joe Celko's book, "Data
> & Databases: Concepts in Practice". He says (in section 8.2, under
> the heading "Multivalued Logic"):
>
> A NULL cannot be compared to another NULL or to a value
I mean that I am not sure NULL is a valid constant in a where clause
comparison.
Thus it could be, that NULL in "where column = NULL" is not defined
to have a special meaning according to SQL92.
NULL is probably only defined in a special context, like:IS NULLIS NOT NULL
Andreas
