Select action that only outputs columns in the source with values

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Posted on by Cgangweg01

893 Super User 2026 Season 1

Hello,

I have a business user who created a multi question/condition MS Form, in which, depending on the answers, goes down different paths. Only certain fields are filled in each time. When the form is submitted, I'd like to build a record of just the values that have been filled in. The empty columns can be ignored. Do I do this with a Select action and expressions? Or is there another way?

Thanks for any guidance!

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Sunil Kumar Pashikanti 2,318 Moderator on at

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Hi @Cgangweg01,

Select + expressions is the correct and supported pattern, but it must be combined with a filter step.

Important limitation:
The Select action by itself cannot conditionally remove properties. It always outputs all mapped keys, even when values are empty.

Recommended Pattern

Convert the form response into a key‑value object

Convert that object into an array

Filter out empty values

Rebuild a clean object containing only populated fields (Optional)

This pattern:

Works reliably for branching MS Forms
Scales well as questions change
Avoids dozens of Conditions or hard‑coded branches
Produces a clean, reusable output

Step 1:
Map each question name to its response:
{
"End Date": outputs('Get_response_details')?['body/EndDate'],
"Seafood": outputs('Get_response_details')?['body/Seafood'],
"Perishable or Total": outputs('Get_response_details')?['body/Perishable']
}

Sept 2:

Convert object to array
union(body('Compose'), body('Compose'))

Step 3:
Filter out empty values
not(empty(item()?['Value']))

https://learn.microsoft.com/power-automate/use-expressions

https://learn.microsoft.com/power-automate/data-operations

✅ If this answer helped resolve your issue, please mark it as Accepted so it can help others with the same problem.
👍 Feel free to Like the post if you found it useful.

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Cgangweg01 893 Super User 2026 Season 1 on at

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Hi @Sunil Kumar Pashikanti

Thank you!

So, step two basically creates a record in the array of each field in the response whether it has a value or not. Then filter the empty out. Is that it?

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Sunil Kumar Pashikanti 2,318 Moderator on at

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Hi @Cgangweg01,

Yes. Step 2 converts the response object into individual key‑value records (including empty ones). Step 3 filters out the empty values, leaving only the fields that were actually answered.

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Chriddle 8,708 Super User 2026 Season 1 on at

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The function union() cannot convert an object into an array.

Try this instead:

xpath( xml( addProperty( json('{}'), 'Root', outputs('Compose') ) ), '/Root/*[. != ""]' )

json(item())

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Cgangweg01 893 Super User 2026 Season 1 on at

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Hi @Chriddle,

Thanks for the solution for removing the empty property key/value pairs in my data set (the form response details). I got the same structured output that you did with my form test data now.

However, I need these to be in a single object. Like this as it was.

[

{

"End Date": "2026-04-17",

"Perishable or Total": "Perishable"

}

]

I've tried an add property function in an apply to each with a variable as well as some other variations. Can't get anything to work even with some assist from Copilot.

What do you suggest? Any xpath wizardry for this?

Thanks again,

Chris

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Chriddle 8,708 Super User 2026 Season 1 on at

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Easiest: Use function union()

union( coalesce(outputs('Compose')?[0], json('{}')), coalesce(outputs('Compose')?[1], json('{}')), coalesce(outputs('Compose')?[2], json('{}')) )

Add an according parameter to the union function for each property of the original object (before filtering for empty properties).

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Chriddle 8,708 Super User 2026 Season 1 on at

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If the above is not possible (e.g., because you don't know the maximum number of object properties) and you are not processing nested objects, you can also manipulate the JSON string.

first( json( replace( string(outputs('Compose')), '},{', ',' ) ) )

Same result as above.

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