Message-ID: <473AE27E.6050103@archonet.com>
Date: Wed, 14 Nov 2007 11:56:46 +0000
From: Richard Huxton <dev@archonet.com>
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To: Julien Cigar <jcigar@ulb.ac.be>
CC: pgsql-sql@postgresql.org
Subject: Re: ALL() question
References: <1195047542.3190.9.camel@frodon.be-bif.ulb.ac.be>
In-Reply-To: <1195047542.3190.9.camel@frodon.be-bif.ulb.ac.be>
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Julien Cigar wrote:
> 
> What I would like is a query that returns all the specimen_id of 
> this table which have _all_ the given test_bit_id. 
[snip]
> With the following I got a syntax error:
> select specimen_id 
> from specimen_test_bits 
> where test_bit_id = all(1,2,3,4);

It's expecting an array here. You'd have to write
  = all('{1,2,3,4}')
But that would have the same problem as...

> The following works but no rows are returned :
> select specimen_id 
> from specimen_test_bits 
> where test_bit_id = all(select id from test_bits where id in (1,2,3,4));

It's testing each row individually and of course one row can't match ALL 
four values.

What you want to do is count the distinct values. Something like:

SELECT
   specimen_id
FROM foo
GROUP BY
   specimen_id
HAVING
   count(distinct test_bit_id) = 4
;

-- 
   Richard Huxton
   Archonet Ltd