From: Bruce Momjian <bruce@momjian.us>
To: sprakash24oct@gmail.com
To: pgsql-docs@lists.postgresql.org
Subject: Re: 7 decimal digits precision for real
Date: Mon, 3 Aug 2020 17:21:35 -0400
Message-ID: <20200803212135.GF17519@momjian.us> (raw)
In-Reply-To: <159614830974.681.17017141356953934189@wrigleys.postgresql.org>
References: <159614830974.681.17017141356953934189@wrigleys.postgresql.org>
On Thu, Jul 30, 2020 at 10:31:49PM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/12/datatype-numeric.html
> Description:
>
> When I try to run
> `insert into employees (r_id) values (3.919192199);`
> where r_id is of type real, I see it stores as 3.9191923 and not 6.
> Am I understanding anything wrong ? isn't the range specified is 6 digits
> precision?
Those extra digits are not guaraneteed to be precise, but usually are
close to accurate, so we include, them. You can diable that with
extra_float_digits = 0:
SELECT '3.919192199'::real;
float4
-----------
3.9191923
SHOW extra_float_digits;
extra_float_digits
--------------------
1
SET extra_float_digits = 0;
SELECT '3.919192199'::real;
float4
---------
3.91919
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
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To: pgsql-docs@postgresql.org
Cc: bruce@momjian.us, sprakash24oct@gmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: 7 decimal digits precision for real
In-Reply-To: <20200803212135.GF17519@momjian.us>
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