本机JPA查询和SQL查询没有给出相同的结果

Question

我有两个表：一个名为issues，另一个名为time_entries，其中id_issue为外键。我根据id_issue列进行了INNER JOIN。

SELECT
    SUM(time_entries.hours)
    , issues.id
    , time_entries.created_on
    , time_entries.updated_on
    , issues.`estimated_hours`
    , issues.`done_ratio`
FROM
    issues
INNER JOIN
    time_entries
ON
    issues.id = time_entries.issue_id 
WHERE
    issues.project_id = 2
GROUP BY
    issues.id

我将此查询放在本机查询中：

Query query = (Query) this.em.createNativeQuery(
              "SELECT " +
              "    SUM(time_entries.hours) " +
              "    , issues.id " +
              "    , issues.estimated_hours" +
              "    , issues.done_ratio" +
              "FROM " +
              "    issues " +
              "INNER JOIN " +
              "    time_entries " +
              "ON " +
              "    issues.id = time_entries.issue_id " +
              "WHERE " +
              "    issues.project_id = 2 " +
              "GROUP BY " +
              "   issues.id");
List<?> result = query.getResultList();

当我执行这两行Java代码时，我得不到与在MySQL控制台中执行此查询相同的结果，但我在跟踪中得到了相同的查询。