Running / rolling sum in a timeseries chart

Situation:

You want to display how some variable changed over time on a chart and therefore need to use rolling sum. The charts only show totals for the time period and not how overall totals change over time.

Solution:

To achieve this you will need to use the report variables instead. The timeseries chart will have a category (time), a series (some grouping criteria) and the measure that will be variable which we want to track.

• We would need to first sort the dataset based on the category and series by creating two sort fields for these two fields.
• Then create a group in a report. The group expression should be set to the field that is used in the chart series.
• Now we will need to create a variable with desired calculation type (count, sum), increment type: none, reset type: group we created previously
• Add the measure, set value expression to be $V{ourVariable}, calculation type: nothing

See attached JRXML file for reference.

timeseries.jrxml