Re: Does Codd's view of a relational database differ from that of Date&Darwin? [M.Gittens]

In article <P0tpe.7445$F7.5240_at_news-server.bigpond.net.au>, hobbit_at_southern_seaweed.com.op says...
> >>Not exactly: SQL ignores NULLs in aggregate functions (except COUNT(*)).
> >>It is not treated as zero for AVG, for instance. Also note that x + NULL
> >>evaluates to NULL; therefore, SQL's SUM is not iterated addition -- it
> >>has a much more complicated definition.
> >
> > Thanks for the clarification.
>
> On the contrary, the answer is wrong for the MS TSQL.
> The AVG and SUM commands ignore nulls - they are
> not treated as *anything*, which in fact, they're not.

Isn't that what I said? "SQL ignores NULLs in aggregate functions (except COUNT(*))."

> And x + NULL does not evaluate to NULL but x.

I should have mentioned that I am talking about the SQL2 standard (or SQL/92 or SQL:1992 or SQL-92 or whatever it is called). I am not familiar with MS TSQL.

-- 
Jon