mysql查询中的重复列名错误

Question

如果fromm我的查询并且不知道如何解决我的查询,我会收到重复列名称的错误

SELECT distinct(courseid+senderid+recipientid) as diskey,
       mess.id,
       User.firstName as recipientName,
       Course.name,
       senderid,
       recipientid,
       courseid,
       message,
       mess.status,
       mess.createdOn 
FROM 
(
    SELECT * 
    from Message,User,Course 
    where Message.recipientid=User.id 
        and Message.courseid=Course.id 
    order by Message.createdOn DESC
) as mess,
     User,
     Course 
WHERE senderid ='3' 
      OR recipientid='3' 
GROUP BY diskey;    

可以任何一个人

Answer 1

为避免重复,请使用表格为列名添加前缀,如下所示:

tab_name.col_name