mysqlの：私はMEMBER_ID 1 のすべてのメンバーとの最後の会話を取得する必要がありますmysqlの

Question

内のすべてのメンバーとメンバーの最後の会話を取得し、次のスクリーンショットで見てください。

here are the tables. members and conversations

how i want高度な

Answer 1

SET @member = 1; /* change to the member id you want to select*/ 

SELECT c.member_id, 
     m.first_name, 
     m.last_name, 
     c.message, 
     c.msg_time 
    FROM (SELECT member_id, 
       message, 
       msg_time, 
       @row_number := CASE WHEN @convid = conv_id 
            THEN @row_number + 1 
            ELSE 1 
           END AS rnum, 
       @convid := conv_id as grp_id 
      FROM (SELECT CASE WHEN sender_id = @member 
          THEN CONCAT(sender_id, receiver_id) 
          WHEN receiver_id = @member 
          THEN CONCAT(receiver_id, sender_id) 
         END conv_id, 
         CASE WHEN sender_id = @member 
          THEN receiver_id 
          WHEN receiver_id = @member 
          THEN sender_id 
         END member_id, 
         c_id, 
         message, 
         msg_time  
        FROM conversation 
       WHERE receiver_id = @member 
        OR sender_id = @member 
       ) conv 
     ORDER BY conv_id, 
       msg_time DESC 
     ) c 
    JOIN members m 
    ON c.member_id = m.member_id 
    AND rnum = 1 
ORDER BY c.msg_time; 

結果

で

感謝

member_id first_name last_name message  msg_time 
4   Washim  Jahan  are u there? 1504886437 
5   mujahid Jahan  yeah!  1504886537 
3   Monayem Jahan  koi   1504887437 
2   Baijed  Khan  working  1505996437