Birt- How to count the number of childrens of each workitems

Hello

In my case, each workitem has two types of childrens: "new components" and "modified components".

In Birt, I must count for each workitem how many new and modified childrens it has. I did it using birt agregation functions, but when I join Datasets it's not working well.

 Is there a "Group By" equivalent for BIRT in the LINKS table? How can I do something like that?

Select SOURCE_ITEMID, COUNT(TARGET_ITEMID) from LINKS where LINK_TYPE='com.ibm.san.workitem.extension.linktype.gc2cd.new' group by SOURCE_ITEMID

Best regards

Boris