From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
cc: David Hunnisett <david.hunnisett@probit.io>,
        "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Subject: Re: differences between <> and != when using signed values on the
 right hand side
In-reply-to: 
 <CAKFQuwaUT_9i+ni=CVsnxWjzWyOOkv35AmttVR_d-N9zM3e6yw@mail.gmail.com>
References: <B9C40FC5-5FA1-40DF-BC91-114493622F61@probit.io>
 <CAKFQuwaUT_9i+ni=CVsnxWjzWyOOkv35AmttVR_d-N9zM3e6yw@mail.gmail.com>
Comments: In-reply-to "David G. Johnston" <david.g.johnston@gmail.com>
	message dated "Thu, 16 May 2024 07:39:43 -0700"
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Date: Thu, 16 May 2024 12:34:50 -0400
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"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Thursday, May 16, 2024, David Hunnisett <david.hunnisett@probit.io>
> wrote:
>> When using a signed comparison !=3D does not behave like <> if the righ=
t
>> hand side comparator is signed and there is no space between the compar=
ator
>> and the sign

> This is not a bug.  You are seeing practical examples of the behavior
> documented here:
> https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNT=
AX-OPERATORS

Yeah, it would probably have been better to forbid multicharacter
operator names that end in '+' or '-'.  But that ship sailed a long
time ago, so we have this kluge to (effectively) allow it only if
the operator can't be a SQL-standard one.  Thus, in the example
"!=3D-" is being read as a single operator name.

			regards, tom lane