Compare SQL Datasets Workflow

This n8n workflow provides a simple yet powerful way to compare data from two different MySQL queries. It's designed to help you identify differences between two datasets, which can be invaluable for data validation, synchronization, or auditing purposes.

What it does

This workflow performs the following steps:

1. Executes MySQL Query 1: Connects to a MySQL database and executes a user-defined SQL query to retrieve the first dataset.
2. Executes MySQL Query 2: Connects to the same or a different MySQL database and executes a second user-defined SQL query to retrieve the second dataset.
3. Compares Datasets: Takes the results from both MySQL queries and compares them using the "Compare Datasets" node. This node can identify items that are:
   • In Dataset 1 only
   • In Dataset 2 only
   • In both datasets (matching)
   • In both datasets but with differences (if a key is specified for comparison)

Prerequisites/Requirements

• n8n Instance: A running instance of n8n.
• MySQL Database(s): Access to one or more MySQL databases.
• MySQL Credentials: Configured MySQL credentials within n8n for connecting to your database(s).

Setup/Usage

1. Import the Workflow:
   • Download the provided JSON file.
   • In your n8n instance, go to "Workflows" and click "New".
   • Click the "Import from JSON" button and paste the workflow JSON or upload the file.
2. Configure MySQL Nodes:
   • Click on the first "MySQL" node (Node ID: 109).
   • Select or create your MySQL credentials.
   • In the "Operation" field, select "Execute SQL".
   • Enter your first SQL query in the "SQL" field. This query should retrieve the data for your first dataset.
   • Repeat the above steps for the second "MySQL" node (Node ID: 836, though it's currently named "Compare Datasets" in the JSON, it's a MySQL node). Note: The JSON provided only contains one MySQL node and one Compare Datasets node. To compare two datasets, you will need to add a second MySQL node and connect its output to the "Compare Datasets" node.
3. Configure Compare Datasets Node:
   • Click on the "Compare Datasets" node.
   • Connect the output of your first MySQL query to the "Dataset 1" input.
   • Connect the output of your second MySQL query to the "Dataset 2" input.
   • Configure the comparison settings:
     • Key Field: Specify a field name (e.g., id, email) that uniquely identifies records in both datasets for comparison.
     • Return All: Choose whether to return all items or only the differences.
4. Test the Workflow:
   • Click the "Execute Workflow" button to run the workflow and see the comparison results. The "Compare Datasets" node will output separate branches for matching, added, removed, and changed items, depending on your configuration.