An easy way of Printing Aggregations

Setting up a large number of aggregated values like sums, counts or averages can be a dreadful experience in the Pentaho Report Designer.

Calculations are performed by functions and expressions (let me call it just functions). These functions are added in the data tab of the report designer. Each function gets a name under which its result can be referenced. And then it needs to be configured properly. Usually, you have to set at least the field it should work on and the group on which it should reset.

Doing it for one field is not exciting, but ok. Doing it for 10 fields is no longer fun.

If you just want to print the result of that calculation, without ever using it as part of another computation, then here’s an easier way of aggregating data:

(1) Drag a number field onto your report and assign a field name to it (attribute common::fieldname).
(2) Set the aggregation you want to use via the attribute “wizard::aggregation-type”.
(3) Optional: Define the group on which you want to reset. If not defined, the current group is used.

This way of defining aggregations is used by the Report Design Wizard. To see a working example – just generate a report with it and add a summary on the fields.

This entry was posted in Basic Topic, Report Designer & Engine, Tech-Tips on by .

About Thomas

After working as all-hands guy and lead developer on Pentaho Reporting for over an decade, I have learned a thing or two about report generation, layouting and general BI practices. I have witnessed the remarkable growth of Pentaho Reporting from a small niche product to a enterprise class Business Intelligence product. This blog documents my own perspective on Pentaho Reporting's development process and our our steps towards upcoming releases.

2 thoughts on “An easy way of Printing Aggregations

  1. jficheux

    Is there any way to get the report in a EXCEL way but having more than one sheet???
    I mean, I’ve got a report with 3 su-reports, and I need that everyone is in a sheet into the excel file.


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