Re: Logical Implication

On Fri, Nov 06, 2026 at 02:05:23PM -0600, Nathan Bossart wrote:
> On Tue, Oct 06, 2026 at 01:19:31PM -0500, Nathan Bossart wrote:
>> On Sat, Oct 03, 2026 at 06:18:43PM +0200, Vik Fearing wrote:
>>> <acronym>SQL</acronym> uses a three-valued logic system with true,
>>> - false, and <literal>null</literal>, which represents <quote>unknown</quote>.
>>> - Observe the following truth tables:
>>> + false, and unknown; the null value of a <type>boolean</type> and the truth
>>> + value unknown are one and the same. In the truth tables below the left
>>> + operand of a binary operator selects the row, and the right operand the
>>> + column:
>>
>> I find the reorganization to be an improvement, and I intend to commit this
>> one sooner than later. The only thing I'd change is the switch from NULL
>> to "unknown" in the tables. Users deal with NULL at the command level, and
>> the rest of the docs use NULL, so I think the existing text has the right
>> idea by noting once that NULL represents "unknown" and then using NULL
>> throughout.
>
> Concretely, like the attached.

I've committed this one.

--
nathan