Java 限制 JPQL 中的结果数
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Limit number of results in JPQL
提问by coubeatczech
How it is possible to limit the number of results retrieved from a database?
如何限制从数据库中检索到的结果数量？
select e from Entity e /* I need only 10 results for instance */采纳答案by Nayan Wadekar
You can try like this giving 10 results to be fetched explicitly.
您可以尝试像这样给出 10 个要显式获取的结果。
entityManager.createQuery(JPQL_QUERY)
.setParameter(arg0, arg1)
.setMaxResults(10)
.getResultList();
It will automatically create native query in back-end to retrieve specific number of results, if the backend supports it, and otherwise do the limit in memory after getting all results.
如果后端支持，它将自动在后端创建原生查询以检索特定数量的结果，否则在获取所有结果后在内存中进行限制。
回答by Tharaka
You can set an offset too using setFirstResult()
您也可以使用 setFirstResult() 设置偏移量
em.createNamedQuery("Entity.list")
.setFirstResult(startPosition)
.setMaxResults(length);
