nhibernate: can't determine data type of aggregate

Question

Any suggestion how to fix this error? (I'd rather not create an sql view to skirt the issue with the sum aggregate)

"Can't extract the type of one parameter of a HQL function: expression->{TreatmentTime}; check aliases. [select new TherapyMinutesDisciplineByDayDTO( sum(TreatmentTime), 2.0, 3.0, t.TreatmentDate, p.LastName, d.Description ) from TherapyMinutesModule.TherapySession t join t._Patient p join t._Discipline d group by t.TreatmentDate, p.LastName, d.Description]"

Here's the hql:

                    c.HSQL = "select"
                     + " new TherapyMinutesDisciplineByDayDTO( sum(TreatmentTime), 2.0, 3.0, t.TreatmentDate, p.LastName, d.Description )"
                     + " from TherapySession t"
                     + " join t._Patient p"
                     + " join t._Discipline d"
                     + " group by t.TreatmentDate, p.LastName, d.Description"

Answer 1

t.TreatmentTime?

---

Edit:

From comments below since my answer wasn't clear at all (sorry)

replace:

sum(TreatmentTime)

with

sum(t.TreatmentTime)