I've been trying to create a jasper report with a subreport inside. But I don't know how I have to link the main report with the subreport.
Knowage:
1º I created the main report and the subreport individually
2º In the main report, I marked the subreport inside "subreports" section

3º I want to find a way to link the subreport inside Jaspersoft Studio, but I don't know wich "Expression" I have to put in

thank you so much,
regards.