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 标准（带有限制等）？

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);

我只设法写了这样的第一部分：

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

Answer 1

尝试为子查询创建一个单独的条件实例，然后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();