如何选择条件等于null。

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

我收到了错误。那么如何编写HQL以获得与上述sql语句相同的结果？

Answer 1

尝试使用IS EMPTY应该有效。

Answer 2

senderId和receiverId是外键吗？ 如果是，那么假设senderId是Sender表的列，receiverId是Receiver表的列，试试这个：

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

OR

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

Answer 3

我已经通过

解决了这个问题

HQL查询： 来自消息 WHERE senderId =：senderId和receiverId =：receiverId 和dateReceived = null