如何选择条件等于null的位置。

Question

SQL语句：

select * FROM Message
 WHERE senderId = 126 and receiverId = 125
   and dateReceived is null

HQL声明：

 FROM Message
WHERE senderId = :senderId and receiverId = :receiverId
 and dateReceived is null

我出错了。 那么如何编写HQL以得到与上述sql语句相同的结果？

Answer 1

尝试使用IS EMPTY应该可以。

Answer 2

是senderId和ReceiverId外键吗？ 如果是，则假设senderId是Sender表的一列，并且receiveId是Receiver表的一列，请尝试以下操作：

select msg FROM Message msg
 WHERE msg.Sender.senderId = 126 and msg.Receiver.receiverId = 125
   and msg.dateReceived is null

要么

Select msg FROM Message msg
WHERE msg.senderId = :senderId and msg.receiverId = :receiverId
 and msg.dateReceived is null

Answer 3

我已经解决了

HQL查询：在消息来源中senderId =：senderId和receiverId =：receiverId和dateReceived = null