From: Gregory Stark <stark@enterprisedb.com>
To: "Andrew McNamara" <andrewm@object-craft.com.au>
Cc: <pgsql-interfaces@postgresql.org>
Subject: Re: PQexecParams and IN query?
In-Reply-To: <20070511120332.6F61C5CC4B5@longblack.object-craft.com.au>
	(Andrew McNamara's message of "Fri, 11 May 2007 22:03:32 +1000")
Organization: EnterpriseDB
References: <20070511120332.6F61C5CC4B5@longblack.object-craft.com.au>
Date: Fri, 11 May 2007 13:31:27 +0100
Message-ID: <87tzuj1qzk.fsf@oxford.xeocode.com>
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"Andrew McNamara" <andrewm@object-craft.com.au> writes:

> I'm trying to use PQexecParams to do an "IN" query, where the set of
> values is supplied as a single parameter - essentially:
>
>     SELECT * FROM sometable WHERE colvalue IN $1
>
> With $1 as a set or array of some sort. Unfortunately, the above doesn't
> pass parsing.  Is there any way to do an IN query via PQexecParams that
> doesn't involve enumerating the set of values as individual parameters?

No but there is a way to do something equivalent with arrays:

SELECT * FROM sometable WHERE colvalue = any($1::integer[]);

I'm not sure which (if any) drivers have good support for arrays though. I
think with most if not all drivers you'll have to crunch your list of elements
down into a string argument of the form "{1,2,3}" (without the quotes). 

If you're using something more complex than integers then you'll have to deal
with quoting the array elements which will start to get annoying.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com