如何为命名查询设置参数

Question

嗨,我有一个命名查询

@NamedQuery(name = "StudyplanCategory.findByStatusAndLimit",
            query = "SELECT s FROM StudyplanCategory s WHERE 
            s.status =:status LIMIT s.start=:start,s.end=end")

我想设置这样的限制:

@NamedQuery(name = "StudyplanCategory.findByStatusAndLimit", 
            query = "SELECT s FROM StudyplanCategory s WHERE 
            s.status =:status LIMIT s.start=:start,s.end=end")

但这在服务器启动时显示错误.我使用以下代码来调用DAO类中的查询:

Query query = entityManager.createNamedQuery("StudyplanCategory.findByStatusAndLimit");
int end=(start*pageNumber);
query.setParameter("status", status);
query.setParameter("start", start);
query.setParameter("end", end);
return (List<StudyplanCategory>) query.getResultList();

需要设置开始和结束参数.请帮忙.

Answer 1

正如@DataNucleus所说,LIMIT不是JPQL中的有效关键字.这不是指定返回多少行的方法.这是你如何做到的:

@NamedQuery(name = "StudyplanCategory.findByStatusAndLimit", 
        query = "SELECT s FROM StudyplanCategory s WHERE 
                    s.status =:status")

这将是调用命名查询的代码:

Query query = entityManager.createNamedQuery("StudyplanCategory.findByStatusAndLimit");
int end=(start*pageNumber);
query.setParameter("status", status);
query.setFirstResult(start);
query.setMaxResults(end - start);
return (List<StudyplanCategory>) query.getResultList();