Date: Thu, 5 Mar 2020 21:29:12 -0500
From: Bruce Momjian <bruce@momjian.us>
To: sergei.agalakov@gmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: Incomplete or misleading explanation of the data types for
 mathematical operators
Message-ID: <20200306022912.GB10548@momjian.us>
References: <158032651854.19851.16261832706661813796@wrigleys.postgresql.org>
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On Wed, Jan 29, 2020 at 07:35:18PM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
> 
> Page: https://www.postgresql.org/docs/12/functions-math.html
> Description:
> 
> "The bitwise operators work only on integral data types, whereas the others
> are available for all numeric data types. "
> Many math operators silently convert integral data types to double for
> calculations, so the result will not be the same data type as what was
> provided.
> select pg_typeof(10^2::bigint),pg_typeof(10^2::numeric)
> select pg_typeof(|/25::int), pg_typeof(|/25::numeric)
> select pg_typeof(10*10::bigint), pg_typeof(10*10::numeric) 
> 
> Multiplication preserves data type, exponentiation silently converts bigint
> to double, but preserves numeric data type, square root silently converts
> both int and numeric types to double.
> The best would be to explain this behaivior of operators like it was done
> for mathematical functions.

Uh, how does this relate to bitwise operators?  Why would we mention
type changes for things like exponentiation in the bitwise operator
documentation section?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
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