not null - trivial, unexpected behavior

the following behaviour seems inconsistent to me.
I can qualify on nulls, but not on nonullness.

This was tested under 7.1.2

create table A
(   a    text,   b    text
);

insert into A(a) values('a1');
insert into A(a, b) values('a2', 'b2');

select count(*) from A where b = null;      /* Returns 1, ok */
select count(*) from A where b != null;     /* Returns 0 ... not ok! */

What am i missing?  Shouldn't those two sets be complimentary?

john


=====
John Scott
Senior Partner
August Associates

email: john@august.com web: http://www.august.com/~jmscott

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