To use an Aggregator transformation in a mapping, add the Aggregator transformation to the mapping. Then configure the transformation with an aggregate expression and group by ports.
To create an Aggregator transformation:
In the Mapping Designer, click Transformation > Create. Select the Aggregator transformation.
Enter a name for the Aggregator, click Create. Then click Done.
The Designer creates the Aggregator transformation.
Drag the ports to the Aggregator transformation.
The Designer creates input/output ports for each port you include.
Double-click the title bar of the transformation to open the Edit Transformations dialog box.
Select the Ports tab.
Click the group by option for each column you want the Aggregator to use in creating groups.
Optionally, enter a default value to replace null groups.
Click Add to add an expression port.
The expression port must be an output port. Make the port an output port by clearing Input (I).
Optionally, add default values for specific ports.
If the target database does not handle null values and certain ports are likely to contain null values, specify a default value.