Actually, I also think the sum should be 0 for austin, as the sum over an empty set is mathematically defined as 0 (http://en.wikipedia.org/wiki/Empty_sum)

So this result is what I would expect:

austin | 0
jonh | null
mary | null
mike | null

On Tue, Nov 26, 2013 at 1:12 PM, Roberto Cornacchia <roberto.cornacchia@gmail.com> wrote:

Personally I believe the expected result is null in all cases except mike.

3 + null is nulll, not 3, right?

On Tue, Nov 26, 2013 at 1:09 PM, Pedro Salgueiro <pedro.salgueiro@cortex-intelligence.com> wrote:

Hi,

A few weeks ago we encountered an issue with monetdb when summing nulls, grouped by some column. We managed to create a simple test case which reproduces this scenario:

create table test (number int, name varchar(50));

 

insert into test values(1,'jonh');
insert into test values(2,'mike');
insert into test values(3,'mary');
insert into test values(null,'austin');
insert into test values(null,'jonh');
insert into test values(null,'mary');

 

select name, sum(number)
from test
group by name;

The result of this query is:

austin | 0
jonh | 1
mary | 3
mike | 2

But the expected result is:

austin | null
jonh | 1
mary | 3
mike | 2

The version that we are using is Feb2013-SP5.

We found a bug report that could be related to this one, but we are not sure: http://bugs.monetdb.org/show_bug.cgi?id=3388

Should we open a new issue for this one?

Thank you,

Pedro Salgueiro

 

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