Re: Simple math statement - problem

From: "Gregory Williamson" <Gregory(dot)Williamson(at)digitalglobe(dot)com>
To: "Gregory Williamson" <Gregory(dot)Williamson(at)digitalglobe(dot)com>, "Postgres User" <postgres(dot)developer(at)gmail(dot)com>, "pgsql-general" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Simple math statement - problem
Date: 2007-11-30 05:47:44
Message-ID: 8B319E5A30FF4A48BE7EEAAF609DB233015E2FF3@COMAIL01.digitalglobe.com
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A quick experiment shows that if either numerator or denominator are decimal, that is preserved in the end result. Probably true for basic math operations in general.

GW

-----Original Message-----
From: pgsql-general-owner(at)postgresql(dot)org on behalf of Gregory Williamson
Sent: Thu 11/29/2007 10:37 PM
To: Postgres User; pgsql-general
Subject: Re: [GENERAL] Simple math statement - problem

The question:
>
> How can I write statements that returns a decimal?
>
>
billing=# select 1/100;
?column?
----------
0
(1 row)

As you said ...

So make everything decimal:
billing=# select 1.0/100.0;
?column?
------------------------
0.01000000000000000000

Or:
billing=# select 1::decimal/100::decimal;
?column?
------------------------
0.01000000000000000000

I think that when you use integers you lose precision right out the gate. Others can provide better insight I hope ...

HTH,

Greg Williamson
Senior DBA
GlobeXplorer LLC, a DigitalGlobe company

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