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Filter Array fails in Copilot Studios Work flow with Parse JSON output that works in Power Automate

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Posted on by Vektori1

Description
Context: Workflow built inside a Copilot Studio agent, Filter array won't work (Power Automate works with the exact same inputs).
Chain: Power BI "Run a query against a dataset" -> Parse JSON -> Filter array.

What works:

"Run a query against a dataset" (Power BI connector) returns rows correctly, confirmed in the run history with real row data.
"Parse JSON" parses that output successfully (green checkmark, no schema errors).

What fails:

"Filter array," pointed at the parsed rows via the dynamic content picker, fails every run with:

The 'from' property value in the 'query' action inputs is of type 'Null'. The value must be an array.

Inspecting the "From" field shows the inserted expression as:

@body('Parse_JSON')?['results/tables/rows']
This treats results/tables/rows as one flattened string key rather than the correct chained path through two arrays:

@body('Parse_JSON')?['results']?[0]?['tables']?[0]?['rows']

Since no property literally named with slashes exists on the object, this evaluates to null, hence the error.

Confirmed environment-specific: building the identical chain (same dataset query, same Parse JSON schema, same Filter array condition) in a classic Power Automate cloud flow at make.powerautomate.com works correctly, "From" resolves to the rows array and the filter runs as expected. Only the embedded Copilot Studio canvas produces the broken flattened reference.

Question?: Is this a known issue with how the embedded flow canvas resolves/inserts references to nested arrays (two levels deep: array of objects containing another array of objects)? Is there a possible fix to this problem?

Kind regards: Vektori

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Calling actions from Copilot Studio

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Haque 3,791 on at

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HI @Vektori1

@body('Parse_JSON')?['results/tables/rows']
This treats results/tables/rows as one flattened string key rather than the correct chained path through two arrays:

@body('Parse_JSON')?['results']?[0]?['tables']?[0]?['rows']

You written expression treats 'results/tables/rows' as a single key, which is not exist and returns null.

The correct expression should be navigaate the nested arrays and objects explicitly:

@body('Parse_JSON')?['results]?[0]?['tables']?[0]?['rows'] - access first element of result array, then first element of tables array and finally the rows arry.

XPath is your friend in this case - if want to spend times please watch this video.

I am sure some clues I tried to give. If these clues help to resolve the issue brought you by here, please don't forget to check the box Does this answer your question? At the same time, I am pretty sure you have liked the response!

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Valantis 6,857 on at

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Hi @Vektori1,

Your diagnosis is exactly right. The Copilot Studio Workflow canvas flattens nested array paths in the dynamic content picker instead of generating the correct chained index notation. This is a confirmed behavior difference from the full Power Automate canvas.

Fix: don't use the dynamic content picker for the Filter array From field. Switch to expression mode manually and type:
body('Parse_JSON')?['results']?[0]?['tables']?[0]?['rows']

In the Filter array action, click the From field, then switch to the expression tab (or edit in advanced mode) and enter the expression above directly instead of selecting from the picker.

This bypasses the flattened path issue entirely since you're providing the correct path yourself. The Workflows canvas will accept a manually typed expression even when its picker generates a broken one.

Best regards,

Valantis ✅ If this helped solve your issue, please Accept as Solution so others can find it quickly.

❤️ If it didn’t fully solve it but was still useful, please click “Yes” on “Was this reply helpful?” or leave a Like :).

🏷️ For follow-ups @Valantis.

📝 https://valantisond365.com/ 💼 LinkedIn ▶️ YouTube

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Vektori1 50 on at

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Thanks for both answers. I used the “Select” data operation and then “Filter array,” as explained in @Haque’s video, and it works.

- Vektori

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Haque 3,791 on at

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Hi @Vektori1,

Thanks for letting us know you got the solution. Just, out of curiosity, can you please check if this expression "@body('Parse_JSON')?['results/tables/rows']" works in Power Autamte? All data operation that needed inner level value, I am used to with nested navigation of each layer with null (?) check. But slash(/) based navigation is bit of new for me.

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