The following are the steps to add an aggregate column directly from reports pag

• Open the reports tab in edit mode.
  
• Click Add Aggregate Formula link. The Add Aggregate Formula dialog box will open.
  
  
  
  
• Specify the formula name.
  
• Choose the data type.
  
• Build the formula.
  
• Click Ok.
  

Aggregate formula will be created for the associated table and can be used in all reports based on this table.