Why does my n8n MySQL node pass tests without inserting data into the database?

Based on the details provided and how the MySQL node works in n8n, a few things might be happening:

1. Query Execution vs. Data Return:
   When using the MySQL node to perform an insert operation, n8n may return a success message (with an empty data object) even though no rows appear to be inserted. This is because the node reports that the query executed without errors. Note that some operations (like inserts) do not return data rows, so a response like:

   JSONCopied
   {"status":"success","data":{}}

   is typical even if the database isn’t showing new records.

2. SQL Query or Parameters Issue:
   Ensure that the SQL query or the operations you’re using are correctly targeting the table and columns you intend to update. For example, if you’re using query parameters for security (which n8n sanitizes to prevent SQL injection), verify that the table name and column names are provided in a way that the node can correctly substitute them. A common pitfall is using an incorrect table name or a missed parameter value. Double-check your node’s configuration and how the query is written.

3. Credential or Connection Configuration:
   Even though no error is reported, it’s worth ensuring that your credentials are correctly set up (host, user, port, etc.) and that your n8n instance is actually connecting to the intended MySQL database. In some cases, if the wrong database is being targeted (or the credentials point elsewhere), the query might “succeed” against a different instance where the effects aren’t visible.

4. Testing Context vs. Actual Execution:
   Passing the tests in the node’s configuration usually means the connection is good and the syntax is accepted. However, the test doesn’t guarantee that the SQL query is performing the desired mutation. It can help to run the same SQL query directly on your MySQL instance (for example, via a MySQL client) using the same parameters to see if the insert works as expected.

Next Steps

• Review Your SQL: Ensure that your INSERT (or other write) statement is correctly structured and that you’re targeting the proper table and columns.
• Check Query Parameters: If you’re using the Query Parameters field, verify that the parameters are valid and that any expressions resolve correctly.
• Validate Credentials: Confirm that your MySQL node credentials in n8n (host, database, username, and password) are correctly configured and that they point to the MySQL instance you expect.
• Direct Testing: Try executing the same query directly against your database to verify that it produces the expected result.

By following these checks, you should be able to pinpoint why nothing appears in the table despite the node returning a success status. If everything is configured correctly and the query works when run manually, then rechecking the node’s query and parameter setup is the next step.