Re: MAX() of 0 records.

Hi Benoit,

> I once had the same problem with an int4 column and solved it by
> using the function below :
>
> CREATE FUNCTION "nulliszero" (int4 )
> RETURNS int4 AS
> 'SELECT 0 WHERE $1 IS NULL
> UNION SELECT $1 WHERE $1 IS NOT NULL' LANGUAGE 'SQL';
>
> Your request then would look like :
> (...)
>  SET entry_maxprice=nulliszero(MAX(item_price));
> (...)

Thanks, I'm afraid that doesn't help in this context (see attached
sql). I'm sure it will come in handy some time though.

The problem isn't that MAX(item_price) returns null, it's that it
causes an error. From what I have distilled from the bugs/hackers
list where Tom has kindly written a lengthy response/discussion
of the problem it seems that in this situation (when no rows
match the where condition) the MAX (or min or count or any
aggregate function?) would cause an implicit grouping to
occur around a null field which the backend doesn't like.

I'd read Tom's post if you are interested though, it probably
makes more sense!

--
Paul McGarry            mailto:paulm@opentec.com.au
Systems Integrator      http://www.opentec.com.au
Opentec Pty Ltd         http://www.iebusiness.com.au
6 Lyon Park Road        Phone: (02) 9878 1744
North Ryde NSW 2113     Fax:   (02) 9878 1755