如何选择条件等于null的地方。

Question

SQL语句：

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

HQL语句：

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

我得到了错误。那么如何编写HQL来获得与上面的sql语句相同的结果呢？

Answer 1

尝试使用IS EMPTY应该可以工作。

Answer 2

是senderId和receiverId外键吗？ 如果是的话，假设senderId是发件人表中的列和receiverId是接收器表试试这个一列：

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

解决它

HQL查询： FROM消息 WHERE senderId =：senderId和receiverId =：receiverId and dateReceived = null