max(), sum(), next()

[Fredrik Lundh]

Mensanator wrote:

> No it isn't. Nothing is not 0, check with MS-Access, for instance:
> 
> Null + 1 returns Null. Any arithmetic expression involving a
> Null evaluates to Null. Adding something to an unknown returns
> an unknown, as it should.
> 
> It is a logical fallacy to equate unknown with 0.

http://en.wikipedia.org/wiki/Empty_sum

"In mathematics, the empty sum, or nullary sum, is the result of adding 
no numbers, in summation for example. Its numerical value is zero."

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