I'm trying to do a simple HQL query that selects an aggregate expression and an entity. I tried something functionally equivalent to the example shown in the documentation (section 11.5):



This does not work in NHibernate 1.0.1. I get an ADO exception complaining that all of the columns in the underlying table for the selected entity do not appear in the SQL "group by" clause. Apparently NHibernate is supposed to build the SQL "group by" clause appropriately, but doesn't do so ...

I guess it should be : where x is an attribute of cat, eg group by
sylvain_2020

According to examples in the documentation, I shouldn't have to do that. In a typical query where I want to select an aggregate expression, I'll also be selecting 3 or 4 entities, each of which has 15-20 properties. I shouldn't have to worry about what those 45-80 properties are, and shouldn't have to name each one in the HQL query. Anyway, I think the HQL parser would complain because you're not explicitly selecting the properties, you're selecting entities.

I can't tell from the documentation if grouping by entities is supported or not. It's shown in 3 different examples in chapter 11, yet in the section on "GROUP BY", it says you can group by any property. It doesn't actually say you can group by entities. So, it appears to be either

1. Several examples in Chapter 11 are invalid; you can't really group by entities.

2. Section 11.10 "The group by clause" forgot to mention that you can group by entities; it actually works in Hibernate, but is broken in NHibernate.

I'm hoping it's #2, because I really need this feature to work ...

Apparently this was broken in Hibernate 2.1, but was intended to work. I don't know if it was ever fixed or not. If a fix exists, can the fix be ported to NHibernate?

Here is a related related topic from the Hibernate forum:

http://forum.hibernate.org/viewtopic.php?t=950514

I alsou found this bug frustrating. Can it be fixed please?

Another plea for a fix (seems simple enough, enumerate all properties of obj in the order by instead of just the id when selecting obj).

Thanks!

Please report it in JIRA and vote for it.

I reported it in JIRA about a week or more ago.