Feedback-ID: ia2694551:Fastmail
Date: Fri, 7 Oct 2022 12:19:17 +0200
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: benkoshy@hotmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: Comparison Predicates - example - documentation seems
 contradictory?
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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/