Limit number of results in JPQL

问题

How it is possible to limit the number of results retrieved from a database?

select e from Entity e /* I need only 10 results for instance */

回答1:

You can try like this giving 10 results to be fetched explicitly.

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.

回答2:

You can set an offset too using setFirstResult()

    em.createNamedQuery("Entity.list")
      .setFirstResult(startPosition)
      .setMaxResults(length);

来源：https://stackoverflow.com/questions/3479128/limit-number-of-results-in-jpql