How to display the Maximum value out of multiple aggregation fields?

Question:

How do I display the maximum value out of multiple aggregation fields?

Answer: 

To achieve the goal, users can write a custom aggregation and use it in a crosstab report.  Follow these steps:

1. Create a new Crosstab style report. In the screenshot below, the "@Customer_Country" field is specified in the Columns section.  The "Sum of @Cost" and "Sum of @Unit Price" fields are specified in the Summaries section.  
2. In the Resources box of the wizard, click "New Crosstab Formula", create a formula ("Formula1" in below example). The formula is defined as:

   number summaries[]  = [@(@Customers_Country:current, sum(@Cost)), @(@Customers_Country:current, sum(@"Unit Price"))];
   
   return maximum(summaries);

   
   
3. Insert the formula into the Summaries box, as shown in the screenshot below.  Exit the wizard.
4. Run the report.  The screenshot below displays the intended visual result; i.e. the red section contains the maximum values from the aggregate values in the previous rows.

Further Reading

https://documentation.logianalytics.com/logireportdesignerguidev17/content/customagg/cstmagg.htm?Highlight=custom%20aggregation