From: Josh Berkus <josh@agliodbs.com>
To: Katka a Daniel Dunajsky <daniel_katka@hotmail.com>
To: pgsql-sql@postgresql.org
Subject: Re: How to increase precision?
Date: Fri, 2 May 2003 15:32:45 -0700
Message-ID: <200305021532.45697.josh@agliodbs.com> (raw)
In-Reply-To: <Law12-F72YKpDS7hx2700007b3c@hotmail.com>
References: <Law12-F72YKpDS7hx2700007b3c@hotmail.com>
Hey Katka,
> How to increase the precision of calculations in posgresql?
>
> When I run this query:
>
> select 5/2;
>
> I get:
>
> ?column?
> --------
> 2
>
> It should be 2.5 shouldn't it?
Nope! You're thinking like a normal person, not like a database engineer.
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
primer on data types and casting.
--
-Josh Berkus
Aglio Database Solutions
San Francisco
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To: pgsql-sql@postgresql.org
Cc: josh@agliodbs.com, daniel_katka@hotmail.com
Subject: Re: How to increase precision?
In-Reply-To: <200305021532.45697.josh@agliodbs.com>
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