Why do groups appear in different orders on report

问题:

I am currently trying to group data together based on a field "type" using iReports 5.6.0. It seems to work but spreads the groups into different places see example below:

What happens

ID      Name    Location   Type  Cost
1       C1       FRA        Car    2k
2       C1       FRA        Car    2k
3       Transit  USA        Van    10K
4       Custom   USA        Van    20K
5       C2       FRA        Car    4K 

Expected Result:

 Example Data
ID      Name    Location   Type  Cost
1       C1       FRA        Car    2k
2       C1       FRA        Car    2k
5       C2       FRA        Car    4K
3       Transit  USA        Van    10K
4       Custom   USA        Van    20K

I wish the data to come out as the expected result below instead of groups seem to be split up (which I think is it the order data is fed into the report from the application)

I have tried using the keep together option but it doesn't seem to work in this situation.

回答1:

When using grouping in jasper report to get correct output the data needs to already be ordered according to the group expressions used.

See: Grouping Data in JasperReports

You can achieve this by either:

order your datasource through query ORDER BY or if using custom datasource for example Collections.sort()

or

use the <sortField/> element in the report for example <sortField name="myField"/>.

• In iReport IDE open the Report Query Dialog "edit query" and click the "Sort options..." button (bottom of interface)

• In JasperSoft Studio open the dataset and query dialog, find the tab "Order" at the bottom and add your field(s)