Re: [PHP] the opposite of a join?

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2007. 10. 3, szerda keltezéssel 05.21-kor jd.pillion@xxxxxxxxx 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.
> 
>  
> 
> 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

>  
> 
> Thanks
> 
>  
> 
> J
> 
>  
> 

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