Limitations on GROUP?

I tried to excecute a HQL like

the generated SQL doesn't include all mapped properties of ClassA,

select a.objID, a.property1, a.property2, count(b.objID) as num
from TABLE_CLASS A ......
group by a.objID


Actually, the right statement should be like:

select a.objID, a.property1, a.property2, count(b.objID) as num
from TABLE_CLASS A ......
group by a.objID, a.property1, a.property2

Does it mean I have to explicitly put all properties of a class in the HQL statement when using the 'group by' clause?

Thanks in advance

James

Thanks a lot.

James