Question

您好：当我使用hibernate进行一些查询时，我遇到了一个非常奇怪的问题：

这是核心代码：

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    start = sdf.parse("2011-02-22 10:00:00");
    end = sdf.parse("2011-02-22 16:00:00");


    Query q = sess.createQuery("select log.uri,count(log.uri) as num from LogEntry log where log.time between ? and ? group by log.uri order by num desc")
            .setDate(0, start).setDate(1, end);
    System.out.println(q.list()); //here I got 0 result,

    System.out.println("===== Make the start date smaller =========");
    start=sdf.parse("2011-02-21 10:00:00");
    q = sess.createQuery("select log.uri,count(log.uri) as num from LogEntry log where log.time between ? and ? group by log.uri order by num desc")
            .setDate(0, start).setDate(1, end);
    System.out.println(q.list()); //here I got 26 result

    System.out.println("===== Make the end date bigger =========");
    end=sdf.parse("2011-02-23 16:00:00");
    q = sess.createQuery("select log.uri,count(log.uri) as num from LogEntry log where log.time between ? and ? group by log.uri order by num desc")
            .setDate(0, start).setDate(1, end); //here I got 39 result
    System.out.println(q.list());

从上面看，似乎在db中有

“2011-02-22 10:00:00”和“2011-02-22 16:00:00”之间

00结果，但有

“2011-02-21 10:00:00”和“2011-02-23 16:00:00”之间

23结果，

所以这意味着“2011-02-22 16:00:00”和“2011-02-23 16:00:00”之间肯定会有一些结果，但是当我做这个测试时，当前时间是“ 2011-02-22 14:45:00“!!!

另外，我也在数据库中做过测试，

select uri,count(uri) as num from xxx_log where time between 20110222100000 and 20110222160000 group by uri order by num desc

我设置了 23行。

所以我想知道为什么这么令人惊讶？

我的代码有什么问题吗？

BTW，我使用的是mysql 5.1。

更新

这是另一个测试代码，首先使用hibernate，然后使用本机sql：

@Test
public void testSQLAndHibernate() throws ParseException {
    start = sdf.parse("2011-02-22 10:00:00");
    end = sdf.parse("2011-02-22 16:00:00");
    // use hibernate
    Session sess = HibernateUtil.getSessionFactory().getCurrentSession();
    sess.beginTransaction();

    Query q = sess
            .createQuery(
                    "select log.uri,count(log.uri) as num from LogEntry log where log.time between ? and ? group by log.uri order by num desc")
            .setDate(0, start).setDate(1, end);
    System.out.println("get "+q.list().size()+" results by hibernate");

    System.out.println("++++++++++++++");
    // use sql
    SimpleDateFormat sdf_sql = new SimpleDateFormat("yyyyMMddHHmmss");
    String sql = "select uri,count(uri) as num from t_log where time between "
            + sdf_sql.format(start) + " and " + sdf_sql.format(end)
            + " group by uri order by num desc";
    try {
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/db",
                "root", "0000");
        Statement state = conn.createStatement();
        ResultSet rs = state.executeQuery(sql);
        int i=0;
        while (rs.next()) {
            //System.out.println(rs.getString(1) + " " + rs.getLong(2));
            i++;
        }
        System.out.println("get "+i+" results by sql query");
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

输出：

get 0 results by hibernate
++++++++++++++
get 24 results by sql query

同样来自hibernat日志我得到了：

binding parameter [1] as [DATE] - Tue Feb 22 10:00:00 CST 2011
binding parameter [2] as [DATE] - Tue Feb 22 16:00:00 CST 2011

似乎开始和结束日期是正确的

Answer 1

执行System.out.println(end)和System.out.println(start)时的结果是什么？它们是正确的格式吗？

如果时间格式偏离预期，Mysql会产生非常奇怪的结果。

Answer 2

请注意，您通过setDate()传递参数，因此它们被解释为SQL类型DATE。在本机查询的情况下，您将日期作为日期文字传递，我想在这种情况下，它们被解释为TIMESTAMP s。这是HQL和本机查询之间的唯一区别。

因此，请尝试通过setTimestamp()传递参数。

hibernate在数据存在的时间范围内什么都不查询

2 个答案: