Is there a Character limit for column names when Unpivoting data?

[DemoFour]

Morning everyone, 

I have a survey from MS forms that comes out with the questions as the column names. I am then indexing these to get the multiple responses over time, before I unpivot my columns to create a fact table. 

The issue that I have is once i have grouped and indexed my table, when I unpivot the columns I am losing text!?
When I look into the steps in the advanced editor, I can see the text is all there, but on Unpivoting the other columns I am losing text. 

Is there any reason for this? 

I have tried lots of different ways to structure my query, but this issue keeps cropping up. If I group and index after I have pivoted the data, then I index all the questions which is not the required output. 

Any ideas please? 

[lbendlin]

The usual recommendation is to unpivot earlier so your questions and answers are listed long rather than wide.

Pretty sure they have some limit on the column name size, maybe 256 characters or some such.

[DemoFour]

Hi @lbendlin, 

Yes I went on to unpivot and pivot more times than I wanted to get the desired outcome, It was just strange as the original column names came through without a limit, then as soon as I did any transformation work, they then stated to be limited. 

Thanks for posting up your response.  

[lbendlin]

Looks like this came up before

Column header name size issue - Microsoft Power BI Community

Seems to be inconsistent between Power Query and Power BI.

In the example above the size limit for Power Query is 100 characters.