When you run a report in Google Ad Manager, you can choose how to display the data. Select one of the report table structures when you create a report.
This spreadsheet view displays selected report dimensions in its own column, with separate rows for each combination. Use this view for optimal report performance.
Column sorting is only available with this view, and when all results fit on a single page.
This pivot table view displays selected report dimensions within a single column with data aggregated for each dimension value in a hierarchical tree format. For example, each ad unit name might have countries listed below, and then devices below countries.
Exported reports always use the flat table structure, even if you chose to display your data in the "Hierarchical" structure within Ad Manager.