In the Expression transformation, configure the expression to aggregate for each row that the mapping processes.
Add an Expression transformation to the mapping.
Consider the mapping logic before you decide where to place the transformation. The mapping output contains an aggregation of the rows that the Expression transformation receives.
In the Expression transformation, click the
Mapping Outputs
view.
Click
New
to add a mapping output expression.
The Developer tool creates a mapping output with a output name that matches one of the mapping outputs you created at the mapping level. If you have more than one mapping output in the mapping
Properties
, select the appropriate mapping output name to use.
The following image shows the
Mapping Outputs
view in the Expression transformation:
Click the
Expression
column to enter an expression in the Expression Editor.
The expression can contain just a port name or it can contain functions, ports, and parameters.
The following image shows an expression to calculate the Total_OrderAmt in the Expression Editor: