如何编写简单的Hibernate Criteria子查询

Question

如何在Java中将此SQL查询编写为Hibernate JPA Criteria（带限制等）？

SELECT q.*
    FROM queue AS q
    WHERE q.executed = false AND
        q.queued_on = (SELECT min(queued_on) FROM queue WHERE item_id = q.item_id);

我只设法编写第一部分，如下所示：

getBaseCriteria()
    .add(Restrictions.eq("executed", false))
    // Missing Second Where Filter Here
    .addOrder(Order.asc("queuedOn"))
    .list();

Answer 1

尝试为子查询创建单独的条件实例，并简单地添加另一个限制，如下所示：

DetachedCriteria subCriteria = DetachedCriteria.forClass(Queue.class, "sub")
    .add(Restrictions.eqProperty("sub.itemId","main.itemId"))
    .setProjection(Projections.projectionList().add(Projections.min("sub.queuedOn")));

session.createCriteria(Queue.class, "main")
   .add(Subqueries.propertyEq("main.queuedOn", subCriteria ));
   .add(Restrictions.eq("main.executed", false));
   .addOrder(Order.asc("main.queuedOn"))
   .list();