Not able to union my VDM

I have local windows installation of Dremio version “3.1.3-201902130614340856-5cd4808”
I have two virtual VDM with same schema:

  1. AUM_Act4
  2. AUM_Plan4

    both the VDM have exact same column names
    when I try to do Union of these two VDM :
    SELECT Key,Amount,Period1,Version FROM AUM_Plan4
    SELECT Key,Amount,Period1,Version FROM AUM_Act4
    I get an error message stating schemas are different.

Unable to complete query, attempting to union two datasets that have different underlying schemas.
Left: schema(Key::varchar, Amount::double, Period1::union<double, varchar>, version::varchar),
Right: schema(Key::varchar, Amount::double, Period1::varchar, version::varchar

but the schemas are identical, I am not sure what is different here. Can anyone help me here.

Hi @Dinesh

Can you share the profile with us, will help you with this


Check the attached document for the profile, (7.2 KB)

I couldn’t get any clue from the profile, if you are able to make any please let me know that to.

Can anyone help me on this issue?


Hi @Dinesh,

Apologies for the slow response, let me take a look at the query and get back to you shortly.

@Dinesh, it looks like there are 2 underlying physical datasets (PDS) that this union references:

@dinesh.AUM_Prdct_Plan_Data: in this dataset Period is a Union type (if you look at the dataset you’ll see Abc/#.# next to the column name)

@dinesh.AUM_Prdct_Data: in this dataset Period is a VARCHAR type (if you look at the dataset you’ll see Abc next to the column name)

So they can’t be unioned. Try creating a VDS where you convert Period from @dinesh.AUM_Prdct_Plan_Data to a VARCHAR and see if you can use that in the union

Hi ,
Thanks for the response , let me check that and get back to you .

Thanks & Regards