Hi!

I have Parent object, which has a collection of Child objects. Child has an attribute attr1.

I need those Parent objects, which has a Child that has an attr specified by a parameter.

My try:

String query = "from Parent r where r in (select a.parent from Child a where a.attr1=:attr1)";

The problem is that this query can return the same Parent object several times. I need a solution where there is a distinct on Parent, so if there are duplicates, i only get one of those.

I tried "select distinct r from parent r....." but it not works.

Secound, i need the query to be as fast as possible, so if there is a solution that is faster than the above, please give me the details.

Thanks.

How about:




Farzad-

I trid it, and still get duplicate objects. Any idea?

That's weird. What is parent class's mapping? With the distinct you should not get duplicates.



Farzad-

Could that be the problem, that my Parent class doesn't have an implemented equals()?

I would assume the check is done on the primary key and in this case it is the database that is doing the distinct part. The generated sql will help a lot. The mapping too.




Farzad-

Ok, they are not duplicate, just has the same data and that misleaded me. Problem solved, thanks.