suppose i need a sub query to return the age of the 20th child, to use somewhere:

select ...
from ...
where age > AGE_OF_20TH_CHILD

how can i form that as subquery?
select age
from T
where ????

thanks

You don't need to use a subquery.

if you need the 20th child you should make a query like this:

"FROM table_name ORDER BY AGE DESC"

So set the query.setFirstResult(19); // 19 because it start counting by 0
and set the query.setMaxResults(1); // Return just 1 result;
This is a simple query and will retrieve only one result: the 20th child ordered by AGE in descendind order.

This is the correct and efficient way to do this in hibernate.

Hope to have solved your problem

This does not solve my problem.
What you suggest is making a separate query only to retrieve the 20th age.
I dont want to make 2 queries.

I have 1 query, where one of the many conditions is age > 20th_age
thus i needed the sub query.
I cant do setMaxResults on my final query, because the ordering there is different and everything there is different.