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Re: Semantics of SUM

From: Steve Harris <steve.harris@garlik.com>
Date: Sat, 14 Nov 2009 06:05:13 +0000
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-Id: <D9681651-E80A-4FF1-99DF-A6861386ADC4@garlik.com>
To: Andy Seaborne <andy.seaborne@talis.com>
On 13 Nov 2009, at 17:05, Andy Seaborne wrote:
> Summary :
>  SQL standard requires nulls to be skipped in SUM.
>  MySQL skips errors just like NULLs.
>  PostgreSQL skips nulls and expression errors on sum(val+5)
>  PostgreSQL causes an error on casting error.
>  Addition with + and nulls does not work as sum over nulls.

The last point I'm not sure sure that it's possible to tell is it? As  
SUM skips NULLs, how do you tell the difference?

- Steve

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Received on Saturday, 14 November 2009 06:05:42 GMT

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