Group members by last post

Question

I have a table with messages sent from 1 user to another. I would like to know that all messages sent or received from different users do not match .Ex: 1-2 is the same as 2-1, but since 2 made the last contact with the user, this message will be shown at the top , as well as the name of the user to whom the message was sent or received from someone other than me. Also check if any message has been sent from the same user as 1-1. I also need to get a name. I really appreciate any help. Thanks at Advance.

code

CREATE TABLE if not exists tblA
(
id int(11) NOT NULL auto_increment ,
sender varchar(255),
receiver varchar(255),
 msg varchar(255),
 date timestamp,
 PRIMARY KEY (id)
);

CREATE TABLE if not exists tblB
(
id int(11) NOT NULL auto_increment ,
sno varchar(255),
name varchar(255),
 PRIMARY KEY (id)
);


INSERT INTO tblA (sender, receiver,msg,date ) VALUES
('1', '2', 'buzz ...','2011-08-21 14:11:09'),
('1', '2', 'test ...','2011-08-21 14:12:19'),
('1', '2', 'check ...','2011-08-21 14:13:29'),
('1', '1', 'test2 ...','2011-08-21 14:14:09'),
('2', '1', 'check2 ...','2011-08-21 14:15:09'),
('2', '1', 'test3 ...','2011-08-21 14:16:09'),
('1', '2', 'buzz ...','2011-08-21 14:17:09'),
('1', '2', 'test ...','2011-08-21 14:18:19'),
('1', '2', 'check ...','2011-08-21 14:19:29'),
('1', '1', 'test2 ...','2011-08-21 14:10:09'),
('3', '1', 'check2 ...','2011-08-21 14:21:09'),
('3', '1', 'test3 ...','2011-08-21 14:22:09'),
('3', '2', 'buzz ...','2011-08-21 14:24:09'),
('3', '2', 'test ...','2011-08-21 14:25:19'),
('1', '3', 'check ...','2011-08-21 14:26:29'),
('1', '3', 'test2 ...','2011-08-21 14:27:09'),
('2', '3', 'check2 ...','2011-08-21 14:28:09'),
('2', '3', 'test3 ...','2011-08-21 14:29:09'),
('1', '2', 'check3 ...','2011-08-21 14:23:09');


INSERT INTO tblB (sno, name ) VALUES
('1', 'Aa'),
('2', 'Bb'),
('3', 'Cc');

SMS- , / , . ?

:

http://jesperbylund.com/wp-content/uploads//2011/11/Facebook-Messenger-459x900.png

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, , , .

Bb
Cc

, Aa, .

Answer 1

, , , :

SELECT t1.sender, t1.receiver, MAX(t1.date)
FROM tblA t1
INNER JOIN (SELECT * FROM tblA ) t2 ON t1.sender = t2.sender 
                                    AND t1.receiver = t2.receiver 
                                    AND t1.sender <> t2.receiver
 GROUP BY t1.sender, t1.receiver

Answer 2

, , LEFT JOIN, .

-

SELECT a.msg AS message, b.name AS sender, c.name AS receiver, date FROM tblA a
LEFT JOIN tblB b ON b.sno = a.sender
LEFT JOIN tblB c ON c.sno = a.receiver
WHERE a.sender != a.receiver
ORDER BY date DESC