Jasper Reports：子报表没有数据时不呈现主报表

Question

Situation I have a report which consists of a header and four subreports in the detail area. The subreports get their data by querying a database.

Requirement If all the subreports have no data, then I would like the main report not to generate - similar to the property "When No Data" set to "No Pages".

Problem Each subreport has the property "Remove Line When Blank" checked so each subreport will only print if it has data. However in the main report, the query text is "select 1 from dual" so that it will always print. I want to change this to be dependent on the subreports, so that if all the subreports have no data, it will return nothing and therefore the whole report will not print due to "When No Data" being set to "No Pages".

Answer 1

There should be a way to set the print when expression for you main report to check your subreports for data, and then only show the main report if at least 1 of them does. Something like:

if (subreport1HasData || subreport2HasData || subreport3HasData || subreport4HasData)