休眠標准帶有投影減去第二個投影的別名

Question

我需要按最大字段“ timeStop”減去最小字段“ timeStart”對分組的對象進行排序。 像這樣：

ProjectionList projList2 = Projections.projectionList();
projList2.add(Projections.alias(Projections.max("timeStop") - Projections.min("timeStop"), "tim"));//Compilation error

Criteria criteria = sess.createCriteria(Call.class);
criteria.addOrder(up ? Order.asc("tim") : Order.desc("tim"));

我怎樣才能做到這一點？

Answer 1

使用sqlProjection

Projections.projectionList()
            .add(Projections.sqlProjection("MAX(timeStop) - MIN(timeStop) AS tim",
                    new String[] { "tim" }, new Type[] {IntegerType.INSTANCE}));

休眠類型可以在org.hibernate.type包中找到