Re: null = null

chester c young <chestercyoung(at)yahoo(dot)com> writes:
> the following took me by suprise:
> egg=# select null=null;
> ?column?
> ----------
> t

This is a Microsoft-compatibility kluge that is going away in the next
release, or at least not being enabled by default.

regression=# select version();
version
---------------------------------------------------------------
PostgreSQL 7.2b5 on hppa-hp-hpux10.20, compiled by GCC 2.95.3
(1 row)

regression=# select null = null;
?column?
----------

(1 row)

regression=# select null IS null;
?column?
----------
t
(1 row)

regression=# set transform_null_equals to 1;
SET VARIABLE
regression=# select null = null;
?column?
----------
t
(1 row)

See the 7.2 docs at
http://developer.postgresql.org/docs/postgres/functions-comparison.html

regards, tom lane