如何与JPA查询进行时间戳比较? [英] How to do a timestamp comparison with JPA query?

问题描述

我们需要确保仅对JPQL查询返回最近30天内的结果.下面是一个示例:

We need to make sure only results within the last 30 days are returned for a JPQL query. An example follows:

Date now = new Date();
Timestamp thirtyDaysAgo = new Timestamp(now.getTime() - 86400000*30);

Query query = em.createQuery(
  "SELECT msg FROM Message msg "+
  "WHERE msg.targetTime < CURRENT_TIMESTAMP AND msg.targetTime > {ts, '"+thirtyDaysAgo+"'}");
List result = query.getResultList();

这是我们收到的错误:

<openjpa-1.2.3-SNAPSHOT-r422266:907835 nonfatal user error> org.apache.openjpa.persistence.ArgumentException: An error occurred while parsing the query filter 'SELECT msg FROM BroadcastMessage msg WHERE msg.targetTime < CURRENT_TIMESTAMP AND msg.targetTime > {ts, '2010-04-18 04:15:37.827'}'. Error message: org.apache.openjpa.kernel.jpql.TokenMgrError: Lexical error at line 1, column 217.  Encountered: "{" (123), after : ""

帮助！

推荐答案

因此，您输入的查询不是JPQL(可以通过参考JPA规范来查看).如果您想将字段与日期进行比较，则可以将日期作为参数输入到查询中

So the query you input is not JPQL (which you could see by referring to the JPA spec). If you want to compare a field with a Date then you input the Date as a parameter to the query

msg.targetTime < CURRENT_TIMESTAMP AND msg.targetTime > :param

这不是SQL.

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