From: | "Thomas A(dot) Lowery" <tlowery(at)stlowery(dot)net> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Join question |
Date: | 2003-08-29 01:06:19 |
Message-ID: | 20030829010619.GB3426@stlowery.net |
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Thread: | |
Lists: | pgsql-general |
Does using a union count as one query?
select a from tst_1 where b is null
union
select d from tst_2 t2 join tst_1 t1 on (t1.b = t2.c)
where t1.b is NOT null
On Thu, Aug 28, 2003 at 05:55:27PM -0400, Williams, Travis L, NEO wrote:
> Question,
>
> I have a table (1) with 2 col (a & b) where b can sometimes be null. I
> need a query that if B is null I get back the contents of A.. but if B
> is not null I do a join on it and table (2) col c to get the contents
> of table (2) col d.. I can do this in multiple queries.. but was
> wondering if I could do it in 1.
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