To perform a data lookup using MS SQL as the datasource in NiFi, you can use the LookupRecord processor along with the DBCPConnectionPool and ScriptedLookupService. Here is an outline of the steps you can follow: Create a DBCPConnectionPool service: Go to the NiFi UI and click on the gear icon to access the Controller Services. Click on the "+" button and select "DBCPConnection Pool" Configure the connection pool with the details of your MS SQL database, such as the driver class name, URL, username, password, etc. Create a ScriptedLookupService: In the same Controller Services screen, click on the "+" button and select "ScriptedLookupService". In the ScriptedLookupService, you need to write a Javascript code that will be used to perform the lookup. You can refer to the example code provided in the forum topic How to get DBCP service inside ScriptedLookupService. Configure the LookupRecord processor: Add a LookupRecord processor to your data flow. In the Properties tab, set the "Lookup Service" to the ScriptedLookupService you created in step 2. In the same Properties tab, set the "Connection Pool" to the DBCPConnectionPool you created in step 1. Connect the LookupRecord processor to your data flow, with the input flow file containing the data that you want to enrich.   ... View more