Re: the opposite of a join?
| From: | Zoltán Németh | Date: | Wed, 03 Oct 2007 11:15:23 +0000 |
| Subject: | Re: the opposite of a join? | ||
| References: | 1 | Groups: | php.db php.general |
| Request: | Send a blank email to php-db+get-44103@lists.php.net to get a copy of this message | ||
2007. 10. 3, szerda keltezéssel 05.21-kor jd.pillion@gmail.com ezt írta:
> 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.
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> 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?
>
maybe something like
SELECT * FROM company WHERE (SELECT COUNT(*) FROM contact WHERE
company_id = company.company_id)=0
it's not very efficient, but I don't have any better idea. someone else?
greets
Zoltán Németh
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> Thanks
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> J
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