From: msi77 <msi77@yandex.ru>
To: Neil Stlyz <neilstylz@yahoo.com>
To: pgsql-sql@postgresql.org
Subject: Re: combine SQL SELECT statements into one
Date: Mon, 01 Feb 2010 13:10:51 +0300
Message-ID: <37481265019051@webmail107.yandex.ru> (raw)
In-Reply-To: <995516.81823.qm@web113717.mail.gq1.yahoo.com>
References: <995516.81823.qm@web113717.mail.gq1.yahoo.com>
Hi,
SELECT
(SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-02-01') as count1,
(SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-01-20') as count2,
(SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-01-01') as count3
Serge
> Good Evening, Good Morning Wherever you are whenever you may be reading this.
> I am new to this email group and have some good experience with SQL and PostgreSQL database.
> I am currently working on a PHP / PostgreSQL project and I came upon something I could not figure out in SQL. I was wondering if anyone here could take a look and perhaps offer some guidance or assistance in helping me write this SQL query.
> Please Consider the following information:
> -------------------------------------------
> I have a postgresql table called 'inventory' that includes two fields: 'model' which is a character varying field and 'modified' which is a timestamp field.
> So the table inventory looks something like this:
> model modified
> ------------- ----------
> I778288176 2010-02-01 08:27:00
> I778288176 2010-01-31 11:23:00
> I778288176 2010-01-29 10:46:00
> JKLM112345 2010-02-01 08:25:00
> JKLM112345 2010-01-31 09:52:00
> JKLM112345 2010-01-28 09:44:00
> X22TUNM765 2010-01-17 10:13:00
> V8893456T6 2010-01-01 09:17:00
> Now with the table, fields and data in mind look at the following three queries:
> SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-02-01';
> SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-01-20';
> SELECT COUNT(distinct model) FROM inventory WHERE modified >= '2010-01-01';
> All three of the above queries work and provide results. However, I want to combine the three into one SQL Statement that hits the database one time. How can I do this in one SQL Statement? Is it possible with sub select?
> Here is what result I am looking for from one SELECT statement using the data example from above:
> count1 | count2 | count3
> -------------------------------
> 2 2 4
> Can this be done with ONE SQL STATEMENT? touching the database only ONE time?
> Please let me know.
> Thanx> :)
> NEiL
>
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To: pgsql-sql@postgresql.org
Cc: msi77@yandex.ru, neilstylz@yahoo.com
Subject: Re: combine SQL SELECT statements into one
In-Reply-To: <37481265019051@webmail107.yandex.ru>
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