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To: daq <daq@ugyvitelszolgaltato.hu>
Cc: "Luke Pascoe" <luke.p@kmg.co.nz>, pgsql-sql@postgresql.org
Subject: Re: CAST from VARCHAR to INT 
In-reply-to: <21242862808.20030124112835@ugyvitelszolgaltato.hu> 
References: <01df01c2c354$2bac5a60$3200000a@K2>
	<21242862808.20030124112835@ugyvitelszolgaltato.hu>
Comments: In-reply-to daq <daq@ugyvitelszolgaltato.hu>
	message dated "Fri, 24 Jan 2003 11:28:35 +0100"
Date: Fri, 24 Jan 2003 10:42:29 -0500
Message-ID: <13400.1043422949@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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daq <daq@ugyvitelszolgaltato.hu> writes:
> Make your life easier! :) You must write a function like
> this:

> create function "int4"(character varying) returns int4 as '
>        DECLARE
>               input alias for $1;
>        BEGIN
>             return (input::text::int4);
>        END;
> ' language 'plpgsql';

> When you try the cast varchar_field::integer or varchar_field::int4 Postgres call
> the function named int4 and takes varchar type parameter.

Note that as of 7.3 you need to issue a CREATE CAST command; the name of
the function is not what drives this anymore.  (Though following the old
naming convention that function name == return type still seems like a
good idea.)

			regards, tom lane