JasperReports Groups

Is there a way to use the 开发者_如何学Pythonfirst value of the data within a group?

For example I have the following data:

1 12/1
1 12/5
2 1/2 
3 5/6
3 6/6

I would like for the data output to be: [with groups]

Group Header for 1 start date: 12/1
  [Data]

Group Header for 2 start date: 1/2
  [Data]

Group Header for 3 start date: 5/6
  [Data]

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You can define a variable, let it reset on each group, set the calculation type to 'first' and the expression to the field you want to display.