RE: Consistent Null Handling

Take a table with all nulls in x but at least one row:

sum(x) => null
sum(nvl(x,0)) => 0
nvl(sum(x),0) => 0

Take a table with no rows:

sum(x) => null
sum(nvl(x,0)) => null
nvl(sum(x),0) => 0

S-

On Fri, 3 Sep 2004, Wolfgang Breitling wrote:

> I don't get that. Under what circumstances will sum(x) and sum(nvl(x,0)) give
> different results? I can see it for avg, but for sum?
>
> Quoting Lex de Haan <lex.de.haan_at_naturaljoin.nl>:
>
> > Note however that the following three Oracle expressions are (and always
> > have been) *different*
> > that is, they give *different* results under certain conditions:
> >
> > - sum(x)
> > - sum(nvl(x,0))
>
>

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