Summaries allow you to generate functions for your data, such as count, average, sum, and standard deviation. Summary functions are based on how you initially grouped the data. For example, if you grouped your data according to country, and you have two groups (US and Canada). Then, if you specify to perform a summary break by country group, you will get the summary result for each group.
A summary is a special kind of formula, but it is often used for DBField or an existing formula. Summary functions can also be realized with formula functions. Since summaries are frequently used in reports, JReport provides you with an easy-to-use GUI for this purpose.
The following topics describe summaries in detail:
See an example: The SampleComponents catalog, included with JReport Designer, contains reports that have examples of how summaries could be used in a report. For the example, open <install_root>\Demo\Reports\SampleComponents\UsingFormula.cls.