mysql: Get last conversation records by user [duplicate]

问题

I need to get last conversation records by to_user in Descending order. I have table called messages. Please have a look on the following screen shot:

I want the output in the following manner:

 from_user| to_user | message         | 
  241     |  226    |   How are you?  |
  241     |  256    | Hi test message |

I have tried this query:

SELECT * FROM `messages` where from_user=241 group by to_user order by created DESC

I am getting the following output which is wrong:

Thanks in advance.

回答1:

Try his:

SELECT t1.* 
FROM `messages` AS t1
JOIN (
   SELECT to_user, MAX(created) AS created
   FROM `messages` 
   WHERE from_user=241
   GROUP BY to_user
) AS t2 ON t1.to_user = t2.to_user AND t1.created = t2.created
WHERE from_user=241
ORDER BY t1.created DESC

回答2:

SELECT *
FROM
  (SELECT *
   FROM `messages`
   WHERE from_user=241
   ORDER BY created DESC) as test
GROUP BY to_user

回答3:

Try this

SELECT * FROM `messages` where from_user=241 group by to_user order by id , created DESC

回答4:

If you want all posts of the from_user in one field (misunderstood the question I think):

SELECT group_concat(messages.message) 
    FROM messages 
    WHERE from_user = 241 
    GROUP BY to_user 
    ORDER BY MAX(id) DESC

You have to say by which criteria you want it to be ordered though. You can have the starting of the conversation or last message of the conversation.

来源：https://stackoverflow.com/questions/37719720/mysql-get-last-conversation-records-by-user

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mysql

sql