Tod McQuillin <devin@spamcop.net> writes:
> On Sun, 16 Sep 2001, Kovacs Baldvin wrote:
>> select NULL = NULL;
>>
>> The answer is: true!!!
> This has got to be a bug. NULL is not equal to anything (nor is it
> unequal to anything).
Indeed, this *should* yield NULL. But right now, postgres' parser
rewrites "= NULL" as "IS NULL" for compatibility with certain brain-dead
Microsoft products.
There have been several discussions on pghackers about undoing this bit
of nonstandardness, but so far nothing's been changed. See the
list archives for more detail than you really wanted.
regards, tom lane