Group by columns in charts
For most of the chart types that you can add to a report, you use the Group by option to define a group by column that specifies how to organize the summarized data in the chart. To further organize the summarized data in a chart, you can specify an additional group by column by using the Then group by option.
For example, you have a report with a column chart that shows the number of cases created during a particular time frame grouped by each shopping mall that you manage.
You can use the Then group by option for the chart to refine the results to show the location within each shopping mall for those cases.