DAX Product() function

[D3nnisd]

Hi,

I'm a IT student currently self learning DAX as part of my upcomming internship.  I am using this guide to learn and Contoso Sales sample for this part.  So far its fairly straight forward, until now. I haven't been able to figure out the use of Product.

The guide tells me to use the Product() function and i'm just taking over what the guide says. But now i get a very different result than the guide tells me i should have.

The guide tells me that the result of using Simple Product = PRODUCT(Channel[Channel]) should be 24, but i get 0.791440856024882.  See the following screenshot for refference:

As far as the guide tells me, product should have done 1 x 2 x 3 x 4 = 24 . The information on the MSDN docs doesnt tell me much either.

Anyone able to give me a answer?

Thanks allot!

Cheers, Dennis

[D3nnisd]

@marcorusso@Greg_Deckler@Anonymous

It's a confirmed bug, it'll be fixed in November release!

Thanks for the input!

~ Dennis

[D3nnisd]

Alright , Thanks !

I have made a bug report here: https://community.powerbi.com/t5/Issues/Product-not-giving-right-results-if-data-type-is-a-whole-num...

Thanks for the information! I'll keep on learning :)!

[Greg_Deckler]

Wow, I've been experimenting with this and I can't make heads or tails of what the PRODUCT function is doing. I get some bizarre results such as infinity, etc. that make absolutely no sense what-so-ever. @marcorusso do you have any idea what the PRODUCT function is doing here because it certainly does not seem like it is returning the PRODUCT of a column. I cannot make heads or tails of what it is actually doing.

[marcorusso · Accepted solution]

The Channel column is defined as Whole Number, it should be a Decimal - do that and it returns 24.

That said - it's funny how it behave with an integer! I suggest submitting the issue to Microsoft.

Marco Russo - SQLBI

[D3nnisd]

Thanks @marcorusso ,  @Greg_Deckler and @Anonymous for replying!

Changing it to a decimal did the trick.

This raises 2 questions:

- Where is that 0.79 comming from?

- What is the absolute diffrence between a whole number and a decimal. Can the decimal be seen as a float and a whole number as a integer?  But this still doesnt explain where the 0.79 come from.

I will report the issue to Microsoft.

[marcorusso]

Yes, decimal is a float and whole number is an integer.

I don't know why there is this bug - I just imagined that PRODUCT is a function designed to work with decimal numbers because you usually use it to compute compound interests. However, it should work with integers too - Microsoft should answer for that, I would say it's a bug.

Marco Russo - SQLBI

[Greg_Deckler]

Thanks @marcorusso, that does solve the issue by making it a decimal number. But, as you said, weird!! I have be believe that is a bug.

[Anonymous]

I can get productx to give the expected result

For example on a table consisting of integers 1-9

Measure = 

PRODUCTX ( VALUES ( Table1[Column1] ), Table1[Column1] )

returns 362,880 as expected.

However, 

Measure = 

PRODUCTX ( Table1, Table1[Column1] )

returns 0

Which is identical to just PRODUCT() doesnt return the expected result.

So a workaround for this is to use PRODUCTX over VALUES however as for why PRODUCT itself isnt behaving as expected I have no idea. My instinct is that this is a bug but I cant be sure.