This crosstab report lists the mileage associated with each department. There is a summation of miles per year and by department. "Total Mileage Exp" is a computation based on the Total Department sum. The computation multiplies the sum by a passed in parameter "rate".
|A Crosstab with a Computation|
The data supporting the report is the following Excel spreadsheet. The spreadsheet makes a datasource with four fields: Year, Department, Expense Reports Filed, Miles Driven. "Filed" and Miles Driven are Integers.
|Datasource for Crosstab|
|Link a Main Parameter with a Crosstab Parameter|
|Use a Computation that References a Parameter|
UPDATE 9/6/2012 - Additional Screenshot for Date Rollups
This is a screenshot to go along with several of the comments listed below.
If you have a field from your datasource of java.util.Date, you can use the Crosstab Wizard to define date-based Row Groups. For example, from a single date field on the Main Dataset (called "Date" in the Fields node), I'm prompted to build Row Groups for both Year and Month.
|Two Crosstab Row Groups from a Single Main Dataset Field|