Subject: Re: select question
From: Wei Weng <wweng@kencast.com>
To: gry@ll.mit.edu
Cc: pgsql-sql@postgresql.org
In-Reply-To: <20020828161241.50a8512d.gry@ll.mit.edu>
References: <20020828161241.50a8512d.gry@ll.mit.edu>
Content-Type: text/plain
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Date: 28 Aug 2002 16:21:31 -0400
Message-Id: <1030566092.24266.1.camel@Monet>
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You can use this query

SELECT * FROM T
	WHERE run = 'a' AND wafer = 1 AND test = 'foo'
UNION
SELECT * FROM T
	WHERE run = 'a' AND wafer = 2 AND test = 'foo'
UNION
SELECT * FROM T
	WHERE run = 'a' AND wafer = 3 AND test = 'foo'
UNION
SELECT * FROM T
	WHERE run = 'a' AND wafer = 3 AND test = 'bar'


On Wed, 2002-08-28 at 16:12, george young wrote:
> [postgreql 7.2, linux]
> I have a table T with columns run, wafer, and test:
>    T(run text, wafer int, test text)
> Given a run and a set of wafers, I need the set of tests that match
> *all* the specified wafers:
> 
> run	wafer	test
> a	1	foo
> a	2	foo
> a	3	foo
> a	3	bar
> 
> E.g.
>   Given run 'a' and wafers (1,3) I should get one row: foo, since only foo matches both 1 and 3.
>   Given run 'a' and wafers (3) I should get two rows: foo,bar, since both foo and bar match 3.
> 
> Is there some neat way to do this in a single query?
> 
> Puzzled,
> 	George
> 
> 
> -- 
>  I cannot think why the whole bed of the ocean is
>  not one solid mass of oysters, so prolific they seem. Ah,
>  I am wandering! Strange how the brain controls the brain!
> 	-- Sherlock Holmes in "The Dying Detective"
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-- 
Wei Weng
Network Software Engineer
KenCast Inc.