From: Martin Marques <martin@bugs.unl.edu.ar>
To: pgsql-sql@postgresql.org
Subject: Best way to know if there is a row
Date: Tue, 28 Sep 2004 09:55:23 -0300
Message-ID: <200409280955.23773.martin@bugs.unl.edu.ar> (raw)
I have a bunch of queries in a system I'm finishing, and I bumped with a
question on performace.
Which is the best way to solve this:
I need to know if there is at least one row in the relation that comes from a
determinated query. Which is the best way to do this:
(a) Build the query with "SELECT * ..." and after executing the query see if
numRows()>0
(b) Build the query with "SELECT count(*) ...", fetch the row and see if
count>0
I'm working with (a) because I see it better in performace, but I wanted to be
sure the numRows() will actually give me the exact amount of rows (had some
problems in the past with Informix).
The aplication is written in PHP.
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Martín Marqués | select 'mmarques' || '@' || 'unl.edu.ar'
Centro de Telematica | DBA, Programador, Administrador
Universidad Nacional
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To: pgsql-sql@postgresql.org
Cc: martin@bugs.unl.edu.ar
Subject: Re: Best way to know if there is a row
In-Reply-To: <200409280955.23773.martin@bugs.unl.edu.ar>
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