Editing Fields in a Data Flow
By default, all fields in a single-segment data source, or all fields from top segment in a multi-segment data source are automatically added to flow. You can turn off this option in the Advanced Options dialog box.
To edit the fields in the flow, right-click the SQL object, and click Edit. The Metadata and Query panes open.
You can add fields to the query or move them to a different part of the query by dragging them to the Order by, Columns, Order Across, and Filters and Variables categories in the Query panel. You can delete a field by right-clicking it and selecting Delete. In addition, you can add all of the fields from a segment ti the Columns or Order by the category by right-clicking the segment name, and clicking Add to Query and either Column or Order by.
A report of the field values opens.
You can also aggregate the data groups by one or more field values. To perform aggregation, click the menu icon for Order By and select Switch to Group By. Drag the columns you want to group by to the Group By field.
Each column in the order by field is assigned a default aggregation, Sum for numeric fields, and Max for others. You can change this by selecting the column and, from the context menu, Aggregation, then the type of aggregation to be performed, such as Sum, Count, or Average.