Hibernate subquery detachedCriteria

问题

How to write a subquery in hibernate which is having multiple subqueries. for example

select * from project_dtls where project_id in  
  (select project_id from project_users where user_id =
  (select user_id from user_dtls where email='abc@email.com'))

I know that we can write through DetachedCriteria but couldnot find any example where I can use multiple subqueries.

回答1:

Here's an example:

DetachedCriteria exampleSubquery = DetachedCriteria.forClass(MyPersistedObject.class)
    .setProjection(Property.forName("id"))
    // plus any other criteria...
    ;

Criteria criteria = getSession().createCriteria(ARelatedPersistedObject.class)
    .setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
    .add(Subqueries.propertyIn("myPersistedObjectId", exampleSubquery)));

For multiple subqueries, you can use a boolean operator like Restrictions.or():

DetachedCriteria anotherSubquery = DetachedCriteria.forClass(MyPersistedObject.class)
    .setProjection(Property.forName("id"))
    // plus any other criteria...
    ;

Criteria criteria = getSession().createCriteria(ARelatedPersistedObject.class)
    .setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
    .add(Restrictions.or(
        Subqueries.propertyIn("myPersistedObjectId", exampleSubquery),
        Subqueries.propertyIn("myPersistedObjectId", anotherSubquery)));

回答2:

To do it entirely with Detached Criteria (because I like to construct the detached criteria without a session)

DetachedCriteria idQuery = DetachedCriteria.forClass(MyPersistedObject.class)
    .setProjection(Property.forName("id"))
DetachedCriteria recordQuery = DetachedCriteria.forClass(MyPersistedObject.class)
    .add(Property.forName("id").eq(idQuery) );

来源：https://stackoverflow.com/questions/13075390/hibernate-subquery-detachedcriteria