网站的两个用户之间的对话类型收件箱消息

Question

我想实现两个用户之间的对话类型的收件箱消息，其中对话将在两个用户之间分组并显示在收件箱页面上，当单击对话时，总体聊天记录将显示在两个用户之间....数据库模式，但未能对两个用户之间的对话进行分组。我需要一个查询来实现此目的。谢谢，这是我的表。

1. 用户：

• ID
• 用户名
• 密码

2. 对话：

• conversation_id
• FROM_USER
• to_user

3. 消息：

• MESSAGE_ID
• conversation_id
• 用户身份
• MESSAGE_TEXT
• MESSAGE_DATE
• 看到

因此，如果有人知道如何实现此查询，那么也请帮助我更改我的架构，谢谢

Answer 1

您可以使用如下所示的查询，通过对话获得当前用户的所有对话以及最后一条消息：

SELECT users.id,
       users.name,
       messages.conversation_id,
       messages.message_id,
       messages.message_text,
       messages.message_date,
       messages.seen
FROM
  (SELECT conversations.conversation_id,
          IF(conversations.from_user = <current_user_id>, conversations.to_user, conversations.from_user) AS interlocutor_id,
          max(messages.message_id) AS last_message_id
   FROM conversations
   LEFT JOIN messages ON conversations.conversation_id = messages.conversation_id
   WHERE convesations.from_id = <current_user_id>
     OR conversations.to_id = <current_user_id>
   GROUP BY conversations.conversation_id) AS t
LEFT JOIN users ON users.id = t.intercolutor_id
LEFT JOIN messages ON messages.message_id = t.last_message_id

如果需要，请使用以下命令获取当前用户与上一次indox消息的所有对话：

SELECT users.id,
       users.name,
       messages.conversation_id,
       messages.message_id,
       messages.message_text,
       messages.message_date,
       messages.seen
FROM
  (SELECT conversations.conversation_id,
          IF(conversations.from_user = <current_user_id>, conversations.to_user, conversations.from_user) AS interlocutor_id,
          max(messages.message_id) AS last_message_id
   FROM conversations
   LEFT JOIN messages ON conversations.conversation_id = messages.conversation_id
   WHERE (convesations.from_id = <current_user_id>
          OR conversations.to_id = <current_user_id>)
     AND messages.user_id <> <current_user_id>
   GROUP BY conversations.conversation_id) AS t
LEFT JOIN users ON users.id = t.intercolutor_id
LEFT JOIN messages ON messages.message_id = t.last_message_id

但是我认为，如果您要重写数据库方案并在“对话”表中添加最后一条消息的ID，那将是更好的方法。 它将使查询更优化

更新：

如果需要获取与当前用户对话的所有用户的列表：

SELECT t.conversation_id,
       users.id,
       users.name
FROM
  (SELECT conversation_id,
          IF(from_user = <current_user_id>, to_user, from_user) AS interlocutor_id          
   FROM conversations   
   WHERE from_id = <current_user_id>
     OR to_id = <current_user_id>) AS t
LEFT JOIN users ON users.id = t.intercolutor_id

PS您必须将<current_user_id>替换为当前用户的实际标识符

Answer 2

SELECT conversation FROM
        conversations

WHERE (conversations.from_user = <user parameter>
OR conversations.to_user = <user parameter>) 
AND conversations.from_user <> conversations.to_user