HQL fails in translating 'group by' construct

g.tomassoni · **Posted:** Fri May 19, 2006 10:02 am

Dears,

I believe to have found a bug in the HQL query translation code. When I attempt to execute the following HQL query:

Code:

select c
from Company as c inner join c.products as p
where c.enabled = true
group by c
having count(p) > 0
order by count(p) desc

the translator yields a sql query like the following:

Code:

select c.id, c.ragSoc, c.idLogo, c.enabled, c.eMail, c.address1, c.address2, c.zip, c.city, c.state, c.idCountry, c.phone, c.fax, c.vat, c.site
from comp.companies c inner join prod.companyProducts p on c.id=p.idCompany
where c.enabled=true
group by c.id
having count((p.idProduct, p.idCompany))>0
order by count((p.idProduct, p.idCompany)) desc

which is basically wrong to my postgresql 8.0. It should be:

Code:

select c.id, c.ragSoc, c.idLogo, c.enabled, c.eMail, c.address1, c.address2, c.zip, c.city, c.state, c.idCountry, c.phone, c.fax, c.vat, c.site
from comp.companies c inner join prod.companyProducts p on c.id=p.idCompany
where c.enabled=true
group by c.id, c.ragSoc, c.idLogo, c.enabled, c.eMail, c.address1, c.address2, c.zip, c.city, c.state, c.idCountry, c.phone, c.fax, c.vat, c.site
having count((p.idProduct, p.idCompany))>0
order by count((p.idProduct, p.idCompany)) desc

Is there any way to circumvent the problem? I would like to retrieve all the companies having products, ordered by descreasing number of offered products. Please note that using a sorted set wouldn't work: there are 2k products and dereferencing c.products would start a slow (and useless) loading of the product's details...

Oh, also note that, as long as I'm using a "inner join", the "having" construct is useless. I left this because this way the query is much more close to the one reported @ page 150 of the hibernate_reference.pdf v. 3.1.3:

Code:

select cat
from Cat cat
join cat.kittens kitten
group by cat
having avg(kitten.weight) > 100
order by count(kitten) asc, sum(kitten.weight) desc

Cheers,

giampaolo

Hibernate version: 3.2 cr2 (same problem with 3.0.5, too)

Mapping documents:

Code:

   <class name="it.mycomp.myapp.persistence.company.Company"
    schema="comp" table="companies"
   >
      <id name="id"><generator class="native"><param name="sequence">comp.companies_id_seq</param></generator></id>

      <property name="ragSoc"
       type="java.lang.String"
       length="32"
       not-null="true"
       unique="true"
      />

      <many-to-one name="logo"
       class="it.mycomp.myapp.persistence.image.Image"
       column="idLogo"
      />

      <property name="enabled"
       type="boolean"
       not-null="true"
      />

      <property name="eMail"
       type="java.lang.String"
       length="64"
       not-null="true"
      />

      <component name="postalAddress"
       class="it.mycomp.myapp.persistence.person.PostalAddress"
      >
         <property name="address1"
          type="java.lang.String"
          length="64"
          not-null="true"
         />

         <property name="address2"
          type="java.lang.String"
          length="64"
         />

         <property name="zip"
          type="java.lang.String"
          length="8"
         />

         <property name="city"
          type="java.lang.String"
          length="32"
         />

         <property name="state"
          type="java.lang.String"
          length="32"
         />

         <many-to-one name="country"
          class="it.mycomp.myapp.persistence.tables.Country"
          column="idCountry"
          not-null="true"
         />
      </component>

      <property name="phone"
       type="java.lang.String"
       length="32"
      />

      <property name="fax"
       type="java.lang.String"
       length="32"
      />

      <property name="vat"
       type="java.lang.String"
       length="16"
      />

      <property name="site"
       type="text"
       not-null="true"
      />

      <set name="users"
       inverse="true"
       lazy="true"
      >
         <key column="idCompany" />
         <one-to-many class="it.mycomp.myapp.persistence.company.CompanyUser" />
      </set>

      <set name="products"
       inverse="true"
       lazy="true"
      >
         <key column="idCompany" />
         <one-to-many class="it.mycomp.myapp.persistence.product.CompanyProduct" />
      </set>
   </class>



   <class name="it.mycomp.myapp.persistence.product.CompanyProduct"
    schema="prod" table="companyProducts"
   >
      <composite-id name="primaryKey"
       class="it.mycomp.myapp.persistence.product.CompanyProductPK"
       access="property"
      >
         <key-many-to-one name="product"
          column="idProduct"
          class="it.mycomp.myapp.persistence.product.Product"
         />

         <key-many-to-one name="company"
          column="idCompany"
          class="it.mycomp.myapp.persistence.company.Company"
         />
      </composite-id>

      <property name="availableQty"
       not-null="false"
      />

      <property name="minOrderQty"
       not-null="true"
      />

      <property name="stepOrderQty"
       not-null="true"
      />

      <property name="unitPrice"
       not-null="true"
      />
   </class>

Full stack trace of any exception that occurs:

Code:

15:36:05,968 ERROR [STDERR] org.hibernate.exception.SQLGrammarException: could not execute query
   at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:67)
   at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
   at org.hibernate.loader.Loader.doList(Loader.java:2148)
   at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
   at org.hibernate.loader.Loader.list(Loader.java:2024)
   at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:392)
   at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:333)
   at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
   at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1114)
   at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
   at it.mycomp.myapp.seam.ActiveCompanies.getActiveCompanies(ActiveCompanies.java:76)
   at it.mycomp.myapp.seam.ActiveCompanies$$EnhancerByCGLIB$$b3ecbcbf.CGLIB$getActiveCompanies$0(<generated>)
   at it.mycomp.myapp.seam.ActiveCompanies$$EnhancerByCGLIB$$b3ecbcbf$$FastClassByCGLIB$$f6f04f39.invoke(<generated>)
   at net.sf.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:167)
   at org.jboss.seam.interceptors.JavaBeanInterceptor$1.proceed(JavaBeanInterceptor.java:80)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
   at org.jboss.seam.interceptors.ValidationInterceptor.validateTargetComponent(ValidationInterceptor.java:64)
   at sun.reflect.GeneratedMethodAccessor86.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.OutcomeInterceptor.interceptOutcome(OutcomeInterceptor.java:21)
   at sun.reflect.GeneratedMethodAccessor85.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.RollbackInterceptor.rollbackIfNecessary(RollbackInterceptor.java:30)
   at sun.reflect.GeneratedMethodAccessor84.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.BijectionInterceptor.bijectTargetComponent(BijectionInterceptor.java:33)
   at sun.reflect.GeneratedMethodAccessor83.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.ConversationInterceptor.endOrBeginLongRunningConversation(ConversationInterceptor.java:68)
   at sun.reflect.GeneratedMethodAccessor82.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.BusinessProcessInterceptor.manageBusinessProcessContext(BusinessProcessInterceptor.java:60)
   at sun.reflect.GeneratedMethodAccessor81.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.TransactionInterceptor.doInTransactionIfNecessary(TransactionInterceptor.java:34)
   at sun.reflect.GeneratedMethodAccessor80.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.interceptors.RemoveInterceptor.removeIfNecessary(RemoveInterceptor.java:39)
   at sun.reflect.GeneratedMethodAccessor79.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:87)
   at org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
   at org.jboss.seam.ejb.SeamInterceptor.aroundInvokeInContexts(SeamInterceptor.java:73)
   at org.jboss.seam.ejb.SeamInterceptor.aroundInvoke(SeamInterceptor.java:45)
   at org.jboss.seam.interceptors.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:51)
   at org.jboss.seam.interceptors.JavaBeanInterceptor.intercept(JavaBeanInterceptor.java:39)
   at it.mycomp.myapp.seam.ActiveCompanies$$EnhancerByCGLIB$$b3ecbcbf.getActiveCompanies(<generated>)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
   at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:32)
   at org.jboss.seam.Component.callComponentMethod(Component.java:1202)
   at org.jboss.seam.Component.unwrap(Component.java:1218)
   at org.jboss.seam.Component.getInstance(Component.java:1144)
   at org.jboss.seam.Component.getInstance(Component.java:1114)
   at org.jboss.seam.jsf.SeamVariableResolver.resolveVariable(SeamVariableResolver.java:44)
   at org.apache.myfaces.config.LastVariableResolverInChain.resolveVariable(LastVariableResolverInChain.java:42)
   at com.sun.facelets.el.LegacyELContext$LegacyELResolver.getValue(LegacyELContext.java:134)
   at com.sun.el.parser.AstIdentifier.getValue(AstIdentifier.java:44)
   at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:183)
   at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:71)
   at com.sun.facelets.el.LegacyValueBinding.getValue(LegacyValueBinding.java:56)
   at com.sun.facelets.component.UIRepeat.getValue(UIRepeat.java:143)
   at com.sun.facelets.component.UIRepeat.getDataModel(UIRepeat.java:121)
   at com.sun.facelets.component.UIRepeat.setIndex(UIRepeat.java:305)
   at com.sun.facelets.component.UIRepeat.process(UIRepeat.java:333)
   at com.sun.facelets.component.UIRepeat.encodeChildren(UIRepeat.java:617)
   at com.sun.facelets.tag.jsf.ComponentSupport.encodeRecursive(ComponentSupport.java:234)
   at com.sun.facelets.tag.jsf.ComponentSupport.encodeRecursive(ComponentSupport.java:239)
   at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.
15:36:05,968 ERROR [STDERR] java:540)
   at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:384)
   at javax.faces.webapp.FacesServlet.service(FacesServlet.java:138)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
   at org.jboss.seam.servlet.SeamRedirectFilter.doFilter(SeamRedirectFilter.java:23)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
   at org.jboss.seam.servlet.SeamExceptionFilter.doFilter(SeamExceptionFilter.java:45)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
   at it.mycomp.myapp.web.filter.ClientCacheDisableFilter.doFilter(ClientCacheDisableFilter.java:43)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
   at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
   at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
   at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
   at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
   at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
   at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
   at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
   at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
   at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
   at java.lang.Thread.run(Thread.java:595)
Caused by: org.postgresql.util.PSQLException: ERROR: column "company0_.ragsoc" must appear in the GROUP BY clause or be used in an aggregate function
   at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1512)
   at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1297)
   at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:188)
   at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:430)
   at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:346)
   at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:250)
   at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeQuery(WrappedPreparedStatement.java:236)
   at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
   at org.hibernate.loader.Loader.getResultSet(Loader.java:1669)
   at org.hibernate.loader.Loader.doQuery(Loader.java:662)
   at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
   at org.hibernate.loader.Loader.doList(Loader.java:2145)
   ... 128 more

Name and version of the database you are using: postgresql 8.0

The generated SQL (show_sql=true):

Code:

select company0_.id as id17_, company0_.ragSoc as ragSoc17_, company0_.idLogo as idLogo17_, company0_.enabled as enabled17_, company0_.eMail as eMail17_, company0_.address1 as address6_17_, company0_.address2 as address7_17_, company0_.zip as zip17_, company0_.city as city17_, company0_.state as state17_, company0_.idCountry as idCountry17_, company0_.phone as phone17_, company0_.fax as fax17_, company0_.vat as vat17_, company0_.site as site17_
from comp.companies company0_ inner join prod.companyProducts products1_ on company0_.id=products1_.idCompany
where company0_.enabled=true
group by company0_.id
having count((products1_.idProduct, products1_.idCompany))>0
order by count((products1_.idProduct, products1_.idCompany)) desc

kovarex · **Joined:** Mon Jul 24, 2006 12:48 pm **Posts:** 4

I have exactly the same problem.

guid · **Joined:** Thu Dec 16, 2010 3:07 am **Posts:** 5

Hey me too. I have also been experiencing the same situation for around two days and I have to say there was literally no way I could fix it until now. However I am looking forward for a way to fix this. The errors are exactly the same as you have posted here and I have to admit is kind of frustrating to say the least. Sitting in front of the computer, able to do nothing about it! I have tried emailing the respective people but there have not been any replies until now. Hope someone comes with a remedy soon!

g.tomassoni · **Posted:** Thu Dec 16, 2010 6:09 am

There are tons of issue reports in jira about Group By.

Some are resolved, but I guess the problem is somehow dialect-related: HQL group by construct working with MySQL may not work with PostgreSQL.

The hibernate community seems to have spent some efforts about the matter, nevertheless it seems to me the group by construct is not sound and solid as it should be.

I personally worked around it by using native queries and/or a subselect-based <table> (which needs Hibernate constructs, it can't be done using only the stock JPA ones).

This is an excerpt from one of my (old) .hbm.xml:

Code:

   <class name="it.uniroma1.dptu.paul.persistence.objectRevision.RevisionProjection"
    mutable="false"
   >
      <subselect>
   SELECT
      r.id AS idrevision,
      o.id AS idobject,
      (
         SELECT count(*) AS count
         FROM treerevisions
         WHERE
            treerevisions.idrevision = r.id AND
            treerevisions.idobject = o.id AND
            treerevisions."action" = 'L'
      ) AS parentattaches,
      (
         SELECT count(*) AS count
         FROM treerevisions
         WHERE
            treerevisions.idrevision = r.id AND
            treerevisions.idobject = o.id AND
            treerevisions."action" = 'U'
      ) AS parentdetaches,
      (
         SELECT count(*) AS count
         FROM treerevisions
         WHERE
            treerevisions.idrevision = r.id AND
            treerevisions.idowner = o.id AND
            treerevisions."action" = 'L'
      ) AS childattaches,
      (
         SELECT count(*) AS count
         FROM treerevisions
         WHERE
            treerevisions.idrevision = r.id AND
            treerevisions.idowner = o.id AND
            treerevisions."action" = 'U'
      ) AS childdetaches,
      (
         (
            SELECT count(*)
            FROM actorrevisions
            WHERE
               actorrevisions.idrevision = r.id AND
               actorrevisions.idobject = o.id
         ) + (
            SELECT count(*)
            FROM arearevisions
            WHERE
               arearevisions.idrevision = r.id AND
               arearevisions.idobject = o.id
         ) + (
            SELECT count(*)
            FROM attachmentrevisions
            WHERE
               attachmentrevisions.idrevision = r.id AND
               attachmentrevisions.idobject = o.id
         ) + (
            SELECT count(*)
            FROM optionrevisions
            WHERE
               optionrevisions.idrevision = r.id AND
               optionrevisions.idobject = o.id
         )
      ) AS contentchanges
   FROM revisions r, objects o
   WHERE r.idsigner IS NOT NULL
   GROUP BY r.id, o.id
      </subselect>

      <composite-id class="it.uniroma1.dptu.paul.persistence.objectRevision.ObjectRevision"
       mapped="true"
       access="field"
      >
         <key-many-to-one name="revision"
          column="idRevision"
          lazy="false"
         />

         <key-many-to-one name="object"
          column="idObject"
          lazy="false"
         />
      </composite-id>

      <property name="parentAttaches"
       column="parentAttaches"
       not-null="true"
      />

      <property name="parentDetaches"
       column="parentDetaches"
       not-null="true"
      />

      <property name="childAttaches"
       column="childAttaches"
       not-null="true"
      />

      <property name="childDetaches"
       column="childDetaches"
       not-null="true"
      />

      <property name="contentChanges"
       column="contentChanges"
       not-null="true"
      />
   </class>

Celestejonas · **Joined:** Wed Sep 21, 2011 9:34 am **Posts:** 6

As far as I know group by has only been added in NHibernate 3.0, but even when using version 3, I can't get group by to work.
I have tried to do the following query:
Session.Query().GroupBy(gbftr => gbftr.Tag).OrderByDescending(obftr => obftr.Count()).Take(count).ToList();
But I receive the following error:
Antlr.Runtime.NoViableAltException'. [. OrderByDescending (. GroupBy (NHibernate.Linq.NhQueryable `1 [Forum.Core.ForumTagRelation] Quote ((gbftr,) => (gbftr.Tag)),), Quote ((obftr,) => (. Count (obftr,))),)]

Does anyone have an idea if I might be mistaken, and group by isn't implemented in NHibernate 3.0, or who knows what I might be doing wrong?