> Is the following statement documented/supported?
> I can't find it documented in BOL the results for Aggregate functions when
> there is no input data.
>
>
> If a Aggregate function gets 0 records input, it returns null.
>
> eg.
>
> SELECT
>  MAX( Field ) AS ReturnsNull
> FROM
>  (
>   SELECT TOP 0 1 AS Field
>  ) NoRecords

"Erland Sommarskog" <esq***@sommarskog.se> wrote in message
news:Xns96F6808DFCEA4Yazorman@127.0.0.1...
> Rebecca York (rebecca.york {at} 2ndbyte.com) writes:
> > Is the following statement documented/supported?
> > I can't find it documented in BOL the results for Aggregate functions
when
> > there is no input data.
> >
> >
> > If a Aggregate function gets 0 records input, it returns null.
> >
> > eg.
> >
> > SELECT
> >  MAX( Field ) AS ReturnsNull
> > FROM
> >  (
> >   SELECT TOP 0 1 AS Field
> >  ) NoRecords
>
> It is actually in Books Online, but it was not too easy to find it. Try
> Accessing and Changing Relational Data
>    Query Fundamentals
>       Advanded Query Concepts
>          Using Aggregate Functions
>             Null Values
>
> Here is says:
>
>    If no rows meet the condition(s) specified in the WHERE clause, COUNT
>    returns a value of zero. The other functions all return NULL. COUNT(*),
>    counts each row, even if all column values are NULL.