Hi...I am newbie to hibernate. I have this problem with outer join. I have two tables table1 and table2:
Table1:
ID
field1
field2

Table2
ID
field3
field4

There is no relationship from tables and I want perform this SQL join:
select * from Table1 left outer join Table2 on Table1.field1=Table2.field4

How can I do this with HQL if in the mapping there is no relation between field1 in Table1 and field4 on Table2?
Sorry for my bad english. Thanks a lot.

HQL works on the object model, not on database tables. In other words, if there is no mapped association you can't perform a join with HQL.

Thanks nordborg.
So if I want make an outer left join I must create a relation between entities? For example a many to many relation between field1 and field4? And in this case, can exist an object of Table2 with field4 that have a value that not exist in a object of Table1? In other words, with a relation between that fields I can have a table2 object with a value of field4 that haven't a corresponding value of field1 in a object of entity Table1?

@tegolo

As nordborg said, you need mapped your entities first. HQL does allow you to perform OUTER JOIN after you have corrected mapped the associations, if that's what you asking. The fact that you said two tables have fields that must equals, they are "related". Read the user manual and try HQL out on your own. repost if you have specific error with code sample.

Also, Hibernate supports native SQL query if you must resort to that. See doc for details.

I don't see how this can be a many-to-many relation in Hibernate terms. It usually requires a join table that holds the relation. Is this some kind of legacy database that you can't change? If so, it may be that using native SQL is your best option. Otherwise I suggest that you redesign the tables.

Yes, it is an existing database that I prefer not change and my experience with Hibernate is little...specially my little knowledge of Hibernate is the problem! :-)
I need some fields in a table and I have the necessary to take other fileds. I can find these fields in another table but...there isn't a really relatioship between the tables in classic terms, in logical terms there is a relation between datas but no relationship in DBMS....In other words there is a bad design of DB because field1 and field4 aren't keys...logically I can make Table1 and Table2 in a single table...but this is that I have. I need some fields of Table2 for a PDF report...and these fields are only in that table. I could put interesting fields in Table2 into Table1...but in native SQL I can get datas for my export with a left outer join using field1 and field4 though fields aren't key using: "ON TABLE1.FIELD1=TABLE2.FIELD4" and I thought have the same thing somehow in HQL. But maybe the solution is redesign DB tables or using native SQL.
Anyway thanks a lot nordborg and saltnlight5.

If I have necessary of a inner join I can change query in:

Query myQuery= em.createQuery("SELECT new MyJoin(t1.field1,t1.field2,t2.field3,t2.field4) FROM Table1 t1, Table2 t2 WHERE t1.field1=t2.field4");
List myList= query.getResultList();

But in left outer join I don't know an alterantive method.
Thanks.