Compare Datasets node not working as expected

Describe the problem/error/question

Hi everyone. I stood up n8n for the first time a couple of days ago and am hosting it in a Docker container on my Synology NAS. I’m either having an issue with, or a misunderstanding of, the Compare Datasets node.

I have a single element coming into the node on both the A branch and the B branch, but the node shows that all the values in A only exist in A and not B and that the values in B only exist in B. However, as you can see from the screenshot below, the same values in A are also in B and vice versa.

In the screenshot, the left side is the input from the A branch and the right side is showing what the node is indicating is only in the B branch. I annotated the screenshot to show that what’s in A is also in B and vice versa. There are a total of 29 values on both the A and B sides and I know for a fact that they are the same, but the node is showing otherwise.

Is this a bug in the Compare Datasets node or am I misunderstanding how it works?

What is the error message (if any)?

Please share your workflow

(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

Share the output returned by the last node

Information on your n8n setup

  • n8n version: 1.76.1
  • Database: postgres
  • n8n EXECUTIONS_PROCESS setting : unknown
  • Running n8n via : Docker
  • Operating system: Synology DSM 7.2

Thanks for your help

It looks like your topic is missing some important information. Could you provide the following if applicable.

  • n8n version:
  • Database (default: SQLite):
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app):
  • Operating system: