Developer Transformation Guide > Aggregator Transformation > Developing an Aggregator Transformation
  

Developing an Aggregator Transformation

When you create an Aggregator transformation, define the expression to run against each row. Define a group by port list to return results by.
To create an Aggregator transformation, perform the following steps:
  1. 1. Define the transformation and create the ports.
  2. 2. Configure an aggregate expression on a variable or output port.
  3. 3. Define a group of ports to return aggregate results by.