The Aggregator transformation uses the store ID field as the group by field. A %QuarterlyData% macro input field reads sales data from the following input fields: Q1, Q2, Q3, and Q4.

A %QuarterlyData%_out macro output field is based on the %QuarterlyData% macro input field. To find the sum of sales for each quarter, the macro output field includes the following expression:

SUM(%QuarterlyData%)

.

In the Target transformation, a field rule includes the following output fields in the incoming fields list: Q1_out, Q2_out, Q3_out, Q4_out. In the target field mapping, the Qx_out fields are mapped to the target.

The following image shows the vertical expression macro in an Aggregator transformation:

When the task runs, the expression expands vertically, as follows:

SUM(Q1)
SUM(Q2)
SUM(Q3)
SUM(Q4)

The task groups the data by store when it performs the aggregation and writes the results to the target.