HQL查询返回空结果集 [英] HQL query returning Empty Resultset

问题描述

我有这个 HQL查询，它返回一个空结果集：

  FROM MeetingSchedule ms JOIN FETCH ms.client JOIN FETCH ms.employees JOIN FETCH ms.parts 
 WHERE ms.meetingId =：meetingId; 
  

如果我执行 SQL查询给我结果

  select * from meeting_schedule where meeting_id =？; 
  

如何调试此查询？

空结果集的原因是什么？
$ b PS：

SQL查询只是为了告诉您我的 MeetingSchedule 不为空，我可以发布生成的 SQL查询这里如果你想。

先进的谢谢。

解决方案

这些是2个不同的查询。在HQL中，你使用JOINS而不是SQL。对相同查询的结果进行比较。答案很简单 - 一些关系丢失会导致连接失败，排除给定的结果行。

您显示的SQL的等效值为

  FROM MeetingSchedule ms WHERE ms.meetingId =：meetingId; 
  

我敢打赌，结果不会为空。

I have this HQL query which returns me an Empty Resultset :

FROM MeetingSchedule ms JOIN FETCH ms.client JOIN FETCH ms.employees JOIN FETCH ms.parts 
WHERE ms.meetingId = :meetingId;

If I execute SQL Query gives me result

select * from meeting_schedule where meeting_id = ?;

How to debug this query?

What will be the cause for Empty Resultset ?

PS:

SQL Query is just to inform you that my MeetingSchedule is not null, I can post generated SQL Query here if you want.

Thank you in advanced.

解决方案

Those are 2 different queries. In HQL you are using JOINS while in SQL not. Do the comparision of results of EXACT the same queries. Answer is ratjher simple - some of relations are missing causing join to fail, excluding given row in result.

Equivalent of SQL you have shown is

FROM MeetingSchedule ms WHERE ms.meetingId = :meetingId;

I bet that result will not be empty.

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