Problems with Data Factory 'Flatten' option

Adrian 181 Reputation points

I am trying to use Flaten inside of Data Factory, I keep on getting the error

The inner value type of the 'Unroll by' structure '{Category Numbers}' must be array type (e.g. structue of arrays, array of arrays)

Whilst I just did a 'Split' operation, this is the preview of the column 'Cateogry Numbers' from the previous step.


Does anybody have any idea why this is happening?

Azure Data Factory
Azure Data Factory
An Azure service for ingesting, preparing, and transforming data at scale.
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Accepted answer
  1. KranthiPakala-MSFT 46,427 Reputation points Microsoft Employee

    Hi @Adrian ,

    Thanks for using Microsoft Q&A forum and posting your query.

    We have noticed that one of our engineer has already been engaged on the same query in Stackoverflow and shared few inputs on Flatten transformation : Data Factory not recognising array for 'flatten' operation

    If you still have further queries, please do share a sample of your input/source data (pls remove sensitive information) and expected output so that we can further assist as needed.

    Thank you


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