Hibernate version: 2.1.5

After:
select r.id, sum(w.CenaSp*z.Ilosc) from ...
error:
Hibernate: select rozliczeni0_.rozliczenie_id as x0_0_, sum(wzor2_.CenaSp*zamowienie1_.Ilosc) as x1_0_ from Rozliczenie rozliczeni0_ left outer join ZamowieniePozycja zamowienie1_ on rozliczeni0_.rozliczenie_id=zamowienie1_.zamowieniepozycja_id left outer join Wzor wzor2_ on zamowienie1_.wzor_id=wzor2_.wzor_id group by rozliczeni0_.rozliczenie_id
8912 [main] WARN util.JDBCExceptionReporter - SQL Error: 0, SQLState: HY002
8912 [main] ERROR util.JDBCExceptionReporter - Column name x2_0_ not found in result set.
8912 [main] WARN util.JDBCExceptionReporter - SQL Error: 0, SQLState: HY002
8912 [main] ERROR util.JDBCExceptionReporter - Column name x2_0_ not found in result set.
8922 [main] ERROR util.JDBCExceptionReporter - Could not execute query
org.firebirdsql.jdbc.FBSQLException: Column name x2_0_ not found in result set.
at org.firebirdsql.jdbc.FBResultSet.findColumn(FBResultSet.java:694)
at org.firebirdsql.jdbc.FBResultSet.getField(FBResultSet.java:401)
at org.firebirdsql.jdbc.FBResultSet.getInt(FBResultSet.java:457)


select r.id, sum(w.CenaSp+z.Ilosc) from ...
Works fine

Tested databases: HSQLDB and FirebirdSQL[/b]

It seems one of the element is retriving null ... try using NVL(Oracle function)... as in

select r.id, sum(Nvl(w.CenaSp,0) * Nvl(z.Ilosc,0)) from ...