Hello,

I am trying to figure out how to execute a (native) SQL query and put
the result in a java variable:

select avg(datediff(dc.diffusionEPReelle, dc.accuseReceptionReelle)))
from E37T_T_DateCle ;

This query returns the mean number of days between two date columns,
and i need to gather this number of days.


(a) When executing this code :

Integer o = (Integer) (getSession().createSQLQuery(
"select avg(datediff(dc.diffusionEPReelle, dc.accuseReceptionReelle)))
as {delaiMoyen} from E37T_T_DateCle",
"delaiMoyen", Integer.class).uniqueResult() );

i'm getting the exception :
net.sf.hibernate.MappingException: No persister for: java.lang.Integer


(b) I have also tried to define a class ResultDelaiMoyen which only
contains two methods getDays() and setDays().

ResultDelaiMoyen o = (ResultDelaiMoyen)
(getSession().createSQLQuery(
"select avg(datediff(dc.diffusionEPReelle, dc.accuseReceptionReelle)))
as {delay.days} from E37T_T_DateCle",
"delay", ResultDelaiMoyen.class).uniqueResult() );

The exception becomes :
net.sf.hibernate.MappingException: No persister for: fr.paris.dsti.aea.services.statistiques.ResultDelaiMoyen

(Note: i haven't created any hbm.xml file for the class ResultDelaiMoyen
because there is no corresponding table in the database. )


(c) I've found an example using <return-scalar> , but this doesn't
work for me - the tag is not recognized. Probably because I'm
using hibernate 2.


So, my question is : how can I execute an arbitrary SQL query
in hibernate 2 ?


Thanks,
Adrian Maier

Sorry for the noise. I've found a solution for my problem.
I discovered the method that returns me the JDBC connection,
and i'm using that :

Connection conn = getSession().connection();
Statement stmt = conn.createStatement();
ResultSet r = stmt.executeQuery("select
avg(datediff(dc.diffusionEPReelle, dc.accuseReceptionReelle))
from E37T_T_DateCle dc");
while (r.next()) {
System.out.println("VAL="+r.getInt(1));
}



Cheers,
Adrian Maier