Something went wrong: 'dataType' argument cannot be null

[ecalzavara]

Hi there,

I have a .pbix that just reads .parquet files to see what's inside. I have made a parameter dropdown to choose from a list of available .parquet files in a folder.

It works for some of them, but for others (which I can successfully preview in PowerQuery), when I hit "Apply changes" pbi crashes returning this error:

I have turned off the connection detection in the Data Load feature but nothing changes. It works for some parquet, but for others it throws this error.

Any help?

[Anonymous]

Hi @ecalzavara ,

Can you please share some dummy data that keep the raw data structure with expected results? It should help us clarify your scenario and test to coding formula.

How to Get Your Question Answered Quickly  

Regards,

Xiaoxin Sheng

[ecalzavara]

UPDATE: I have found a workaround but I wouldn't consider it a proper "SOLUTION".

I have noticed that some datatypes were detected with this icon:

I have then added these steps to "reset" the datatype, and it applied the changes successfully.

Though, it would be good to understand why it defines the datatype with a quesiton mark in the first place and.. does anyone know the correct way to make it DEFINE it, rather than my demote/promote workaround?

[ngardnerd]

I ran into the same problem, and I think the reason it does that is because the first 1000 rows of that data are all null. Power BI doesn't know data type to assign the column if all the rows are null