n8n Merge Node Fails to Combine 'customerID' Fields in Workflow 2

Below is a summary of what to check and adjust when you face an empty output in the Merge node in this workflow.

1. Confirm Field Names and Data Structure

The Merge node matches on the exact value provided in the fields specified. In the tutorial, you must merge on the customerID field from Airtable and the same field from the HTTP node. Verify that:

• Exact Naming: The field names are identical. (For example, check for any case differences or extra spaces.)
• Correct Data Path: In some cases the Airtable node returns data nested under a key like fields. Make sure you’re referencing the customerID in the correct path. For example, if your Airtable data is structured as { fields: { customerID: 1, … } }, use an expression (or adjust your settings) so that Merge sees the field with the value.

2. Data Type Consistency

Ensure that both nodes deliver values with the same type. If one side gives a string while the other gives a number (or vice versa), they won’t match. For example:

• If the HTTP node returns customerID as a number (e.g. 1) and Airtable returns it as a string (e.g. "1"), then the merge won’t find a match.
• You might need to cast the values (using a Function or Code node) so that both sides have the same data type.

3. Merge Mode Configuration

The tutorial uses the Merge node in Combine mode with matching fields. Remember that when using Keep Matches:

• Only pairs with matching customerID values produce output.
• If no pair is found, the node returns no output and stops execution.

Also, if you flipped the “Fields to match have different names” switch, double-check that both fields are indeed provided as customerID in each input and that they’re exactly the same.

4. Check Input Order

The Merge node takes Input 1 and Input 2 and processes them according to the mode configuration. Make sure that:

• The right nodes are connected to the corresponding inputs.
• If there’s an expected order (for example, if merging by position) verify that the arrays have matching lengths.

5. Verify and Debug

• Inspect Data: Use the “Execute Node” option for both Airtable and HTTP Request nodes individually to see the exact output structure.
• Always Output Data: Temporarily enable the Settings > “Always Output Data” option so you can see if one side isn’t producing any items.

By ensuring that these aspects are aligned the Merge node should combine the data as expected. The issue is most often due to a mismatch in the field paths or data types, so double-check the outputs from both the Airtable and HTTP nodes to ensure they match on the customerID field.

Let me know if you have any further questions regarding merging in n8n!