For databases that support subselects, Hibernate supports subqueries within queries. A subquery must be surrounded by parentheses (often by an SQL aggregate function call). Even correlated subqueries (subqueries that refer to an alias in the outer query) are allowed.
from Cat as fatcat where fatcat.weight > ( select avg(cat.weight) from DomesticCat cat )
from DomesticCat as cat where cat.name = some ( select name.nickName from Name as name )
from Cat as cat where not exists ( from Cat as mate where mate.mate = cat )
from DomesticCat as cat where cat.name not in ( select name.nickName from Name as name )
select cat.id, (select max(kit.weight) from cat.kitten kit) from Cat as cat
Note that HQL subqueries may occur only in the select or where clauses.
Note that subqueries can also utilize row value constructor
syntax. See
Section 14.18, “Row value constructor syntax” for more details.