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Power Platform Community / Forums / Power Automate - Building Flows / Unable to process temp...
Power Automate - Building Flows
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Unable to process template language expressions in action 'Compose_2' inputs at line '0' and column '0': 'The template language function 'union' expects either a comma separated list of arrays

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Posted on by GulS 3

I have a flow that runs a select on a power BI dataset to get a list of email addresses. The Output produced a list a email addresses with duplicates as follows:

 

GulS_0-1687864105344.png

I then run a compose with 

union(body('Select'),union(body('Select')))

GulS_1-1687864168348.png

This step produces an error
Unable to process template language expressions in action 'Compose_2' inputs at line '0' and column '0': 'The template language function 'union' expects either a comma separated list of arrays or a comma separated list of objects as its parameters. The function was invoked with '1' parameter(s).

GulS_2-1687864267516.png

Any ideas on how to solve?



I have the same question (0)
  • ManishSolanki Profile Picture
    ManishSolanki 15,089 Super User 2025 Season 2 on at
    Re: Unable to process template language expressions in action 'Compose_2' inputs at line '0' and column '0': 'The template language function 'union' expects either a comma separated list of arrays

    Hi @GulS 

     

    To get the distinct email addresses using union() formula, pls try the below expression:

    union(body('Select'),body('Select'))

     

    If this helps & solves your problem, please remember to give a 👍 and accept my solution as it will help others in the future.

     

    Thanks

  • GulS Profile Picture
    GulS 3 on at
    Re: Unable to process template language expressions in action 'Compose_2' inputs at line '0' and column '0': 'The template language function 'union' expects either a comma separated list of arrays

    Thank you. That solved the issue

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