Content-Type: text/plain;
  charset="iso-8859-1"
From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: "Katka a Daniel Dunajsky" <daniel_katka@hotmail.com>,
	pgsql-sql@postgresql.org
Subject: Re: How to increase precision?
Date: Fri, 2 May 2003 15:32:45 -0700
User-Agent: KMail/1.4.3
References: <Law12-F72YKpDS7hx2700007b3c@hotmail.com>
In-Reply-To: <Law12-F72YKpDS7hx2700007b3c@hotmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Message-Id: <200305021532.45697.josh@agliodbs.com>

Hey Katka,

> How to increase the precision of calculations in posgresql?
>=20
> When I run this query:
>=20
> select 5/2;
>=20
> I get:
>=20
> ?column?
> --------
>        2
>=20
> It should be 2.5 shouldn't it?

Nope!  You're thinking like a normal person, not like a database engineer.=
=20=20=20
Translated, here's what you told the database:

Give me INTEGER 5  / INTEGER 2

and the database told you:

INTEGER 2

if you'd asked, the database would also have happily told you:

REMAINDER 1

What you really wanted to ask the database was:

Give me NUMERIC 5  /  NUMERIC 2
 or in SQL:
SELECT 5::NUMERIC/2::NUMERIC

At which point you will get

2.5000 (NUMERIC)

Look for a general book on SQL databases, which should be able to give you =
a=20
primer on data types and casting.

--=20
-Josh Berkus
 Aglio Database Solutions
 San Francisco