From: Jim C. Nasby <jnasby@pervasive.com>
To: Matt Emmerton <matt@gsicomp.on.ca>
Cc: Russell Simpkins <russellsimpkins@hotmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Help with multistage query
Date: Tue, 4 Oct 2005 17:34:50 -0500
Message-ID: <20051004223450.GM40138@pervasive.com> (raw)
In-Reply-To: <003001c5b3f4$6a6911b0$1200a8c0@gsicomp.on.ca>
References: <000001c5b3d5$a67a3540$0300a8c0@dell8200>
<BAY103-DAV13C36CCE265B28F7F39B50B5A60@phx.gbl>
<003001c5b3f4$6a6911b0$1200a8c0@gsicomp.on.ca>
On Wed, Sep 07, 2005 at 05:37:47PM -0400, Matt Emmerton wrote:
>
> ----- Original Message -----
> From: Russell Simpkins
> To: pgsql-sql@postgresql.org
> Sent: Wednesday, September 07, 2005 4:05 PM
> Subject: Re: [SQL] Help with multistage query
>
> I have a perl script that issues a series of SQL statements to perform some queries. The script works, but I believe there must be a more elegant way to do this.
>
>
>
> The simplified queries look like this:
>
>
>
> SELECT id FROM t1 WHERE condition1; ;returns about 2k records which are stored in @idarray
>
>
>
> foreach $id (@idarray) {
>
> SELECT x FROM t2 WHERE id=$id; ; each select returns about 100 records which are saved in a perl variable
>
> }
>
> how about
> select t1.id from t1, t2 where t1.id = t2.id and t2.id = x
>
> or more correctly, based on the OP's example:
>
> select t2.x from t1, t2 where t1.id = t2.id and t1.id = <condition>
Actually, I think you want AND t2.x <condition>, not t1.id.
BTW, I recommend not using id as a bareword field name. Very easy to get
confused when you start joining a bunch of stuff together.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-sql@postgresql.org
Cc: jnasby@pervasive.com, matt@gsicomp.on.ca, russellsimpkins@hotmail.com
Subject: Re: Help with multistage query
In-Reply-To: <20051004223450.GM40138@pervasive.com>
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