From: Date: July 18 2003 4:28pm
Subject: Re: join query result difference between 3.23.49 and 4.0.13
List-Archive: http://lists.mysql.com/mysql/145527
Message-Id: <5pcluxi4s.ln2@blend.ensita.net>

"Rudy Metzger" <rudy.metzger@stripped> wrote:
> Better ifnull(sum(amount_paid),0)

Yes, you are right.

> 
> Because if you add up a column which contains NULL and NOT NULL values,
> all NULL values are SKIPPED for the calculation. 
> 
> This implies that if the column ONLY contains NULL values, the result is
> NULL.
> 
> Would be great if MySQL could post a chart somewhere of how they treat
> NULL values in calculations. Until then, check the release notes for
> every release concerning NULLs. And also the known bugs/future releases.
> 
> 


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