About calculated data
Most BIRT reports require calculations to track sales, finances, inventory, and other critical business activities. You can use Interactive Viewer to create calculations to count items in a warehouse or provide more complex financial data, such as tracking stock portfolio performance over time.
To display calculated data in a report, you create a computed column, such as the Total column in the report shown in Figure 6-1. In the example, you need to calculate the Total because the original report does not provide this data.
Figure 6-1  
In Release 11 Service Pack 4, Interactive Viewer provides a convenient expression builder wizard to create computed data. You use Expression Builder to do one of the following:
Select a function to use, then select one or more columns across which Interactive Viewer performs the calculation.
Select a function, then create an expression and validate it, after which Interactive Viewer performs the calculation.

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