Re: Comparison Predicates - example - documentation seems contradictory?

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От Alvaro Herrera
Тема Re: Comparison Predicates - example - documentation seems contradictory?
Дата
Msg-id 20221007101917.3hturo5a7v25cjh7@alvherre.pgsql
обсуждение исходный текст
Ответ на Comparison Predicates - example - documentation seems contradictory?  (PG Doc comments form <noreply@postgresql.org>)
Ответы Re: Comparison Predicates - example - documentation seems contradictory?  (Ben Koshy <benkoshy@hotmail.com>)
Список pgsql-docs
On 2022-Oct-06, PG Doc comments form wrote:

> See the heading: "Table 9.2. Comparison Predicates"
> 
> "2 BETWEEN 3 AND 1 → f" # ok this is false.
> 
> But let's read the example immediately below (the 'not between' example)
> 
> 2 NOT BETWEEN 1 AND 3 → f   # what? This is also false. how can the negation
> also be the same value? I would expect it to be true?

Actually, 2 *is* between 1 and 3.  So if you ask if it's NOT between,
that's false.

The other one is false because the boundaries are reversed, and BETWEEN
does not put them in the proper order before comparing.  BETWEEN
SYMMETRIC does that, as explained in the line below.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/



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