JPQL限制查询 [英] JPQL limit query

问题描述

如何限制JPQL命名查询的选择查询?我需要在查询级别本身而不是在Java层中完成限制！！！ 我正在尝试使用

How can I limit in a select query of JPQL named query? I need the limit to be done in the query level itself and not in the java layer!!! I am trying to use

@NamedQueries(value = {
        @NamedQuery(name = UserNotification.QueryName.NOTIFICATION_DISPLAYED,
                    query = "SELECT un FROM UserNotification un " +
                            "WHERE un.orgId IN (:orgList) " +
                            "AND un.user.id = :userId LIMIT 5")

但徒劳！！！

请建议

推荐答案

JPQL不提供限制查询的机制.这通常是通过在Query上使用setMaxResults()方法来实现的.如果必须避免在Java代码中进行指定，则可以在包含查询并执行限制的数据库中进行查看.然后将实体映射到此视图，就像创建表一样.

JPQL does not provide a mechanism to limit queries. This is most often achieved by using the setMaxResults() method on the Query. If you must avoid specifying this in Java code, you could make a view in the database that contains your query and performs the limit. Then map an entity to this view as you would a table.

示例:

List<String> resultList= query.setMaxResults(100).getResultList();

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