Joining more than 2 tables

Dearest fellow Mendix users, I have got myself a little problem here. I am trying to join more than 2 tables in a Dataset so the report function wil display them. Eventually it will be about 5 or 6 columns in all. Could someone please tell me what I am doing wrong because i keep getting an error in the runtime environment when generating a report. You can see the OQL i used here: Select Employee/Med_ID as Employee_ID, SUM(PM/Planned_Hours) as Planned_Hours, SUM(BM/Actual_Hours) as Actual_Hours From csys.Employee as Employee inner join csys.Planning_Employee/csys.Planning as PM inner join csys.Billing_Grid_Employees/csys.Billing_Grid as BM GROUP BY Employee/Med_ID And the domain model here:
1 answers

Nick, you're missing a GROUP BY clause. I think you need

 GROUP BY Employee/Med_ID