Effective in version 10.0, you can create mapping outputs that return aggregated values from the mapping run. Mapping outputs are the result of aggregating a field value or an expression from each row that a mapping processes.
For example, you can configure a mapping output to summarize the total amount of an order field from the source rows that the transformation receives. You can persist a mapping output value in the repository. You can assign a persisted mapping output value to the Mapping task input parameter. You can also assign mapping outputs to workflow variables.