Hi, It's not possible to do this type of query using ODMG/OQL.
You have to use the PB API. You can use the PB Style quries from "within" ODMG - see http://db.apache.org/ojb/docu/guides/odmg-guide.html#I+don%27t+like+OQL% 2C+can+I+use+the+PersistenceBroker+Queries+within+ODMG for more details Cheers, Charles. > -----Original Message----- > From: Francesco Martinelli [mailto:[EMAIL PROTECTED] > Sent: 22 November 2006 08:17 > To: Vasily Ivanov > Cc: OJB Users List > Subject: Re: How-To select on a "group" function > > Thank you Vasily, > however I am using ODMG, and I am not sure on how to > integrate your suggestion within ODMG. > > Actually the sequence of instruction I use is the following: > Implementation odmg = OJB.getInstance(); > Transaction tx = odmg.newTransaction(); > tx.begin(); > OQLQuery query = odmg.newOQLQuery(); > String oqlQuery = "select ... from " + (Class)MyClass).getName(); > query.create(oqlQuery); > Object queryResult = query.execute(); > Iterator itr = ((ManageableCollection)queryResult).ojbIterator(); > > Thank you, > Francesco. > > > > Hi Francesco, > > > > You can do the following: > > ReportQueryByCriteria query = > QueryFactory.newReportQuery(Clazz.class, > > new Criteria()); > > query.setAttributes(new String[] { "max(value1)", "value2" }); > > query.addOrderByAscending("max(value1)"); > > query.addGroupBy("value2"); > > Iterator itr = pb.getReportQueryIteratorByQuery(query); > > > > I hope that helps. > > > > Regards, > > Vasily > > > > On 11/22/06, Francesco Martinelli <[EMAIL PROTECTED]> wrote: > >> Hi, > >> > >> I would like to retrieve a record using the following SQL-Like > >> statement: > >> "select max(value) from " + className > >> > >> Does anyone know how to "convert" this to OQL? > >> > >> I know it would be possible to retrieve all the records, then sort > >> them out, and pick up the first, but I would prefer to reduce the > >> amount of data retrieved from the database. > >> > >> I also wonder if it were possible to order the "resultset" > according > >> to one field, e.g. of SQL-like would be: > >> "select xxx from " + className + " order by value". > >> > >> Thenk you, > >> Francesco. > >> > >> > >> > --------------------------------------------------------------------- > >> To unsubscribe, e-mail: [EMAIL PROTECTED] > >> For additional commands, e-mail: [EMAIL PROTECTED] > >> > >> > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
