Re: the opposite of a join?
| From: | James Ausmus | Date: | Wed, 03 Oct 2007 15:35:43 +0000 |
| Subject: | Re: the opposite of a join? | ||
| References: | 1 | Groups: | php.db php.general |
| Request: | Send a blank email to php-db+get-44110@lists.php.net to get a copy of this message | ||
On 10/3/07, jd.pillion@gmail.com <jd.pillion@gmail.com> wrote:
>
> I have a company table and a contacts table. In the contacts table, there
> is a field called "companyID" which is a link to a row in the company
> table.
>
>
>
> What is the easiest way to query the company table for all the company
> rows
> whose ID is NOT linked to in the contact table? Basically, the opposite of
> a
> join?
SELECT company.*
FROM company LEFT JOIN contacts ON (company.companyID = contacts.companyID)
WHERE contacts.companyID IS NULL
(Assuming your DB can handle a left join)
-James
Thanks
>
>
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> J
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