Mysql get latest 10 from each group

Question

I asked a previous question in how to do it in the zend framework way, but no luck, help me get the regular mysql query.

I have tables messages with message_id , thread_id , message

I have a list

$threads = "1,2,3,4,5,6,7,8,9,10,11,12,13,14,15";

I need to find the last 10 messages from each thread.

I was trying something along the lines of

SELECT m2.* FROM messages m2 JOIN(SELECT * FROM messages)m ON m2.thread_id = m.thread_id WHERE m2.message_id IN ('$list') LIMIT 10

but that limits 10 in total.

Any help would be appreciated, thank you.

---

 CREATE TABLE IF NOT EXISTS `messages` (
  `message_id` int(11) NOT NULL AUTO_INCREMENT,
  `thread_id` int(11) NOT NULL,
  `message` text NOT NULL,
  PRIMARY KEY (`message_id`),
  KEY `thread_id` (`thread_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

Sample Data:

    INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1,1,"tempor erat neque");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (101,1,"adipiscing non, luctus sit amet,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (201,1,"fames");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (301,1,"odio. Phasellus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (401,4,"Donec egestas. Aliquam nec enim. Nunc ut");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (501,3,"Aliquam tincidunt, nunc ac mattis ornare, lectus ante dictum mi,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (601,5,"Fusce mollis. Duis sit amet diam eu dolor egestas rhoncus.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (701,2,"non, lacinia at, iaculis quis, pede. Praesent");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (801,6,"vehicula");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (901,2,"mollis nec, cursus a, enim. Suspendisse");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1001,3,"urna. Nullam lobortis quam a felis ullamcorper");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1101,2,"magna. Lorem ipsum dolor sit amet, consectetuer");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1201,5,"erat nonummy ultricies ornare, elit elit fermentum risus,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1301,4,"mattis ornare, lectus ante dictum mi, ac mattis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1401,5,"justo. Proin non massa");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1501,6,"leo, in lobortis tellus justo sit amet nulla.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1601,5,"sit amet, dapibus id, blandit");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1701,1,"cursus luctus, ipsum leo elementum sem, vitae aliquam");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1801,4,"ac ipsum. Phasellus vitae mauris sit amet");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (1901,1,"nunc interdum feugiat. Sed nec metus facilisis lorem tristique aliquet.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2001,2,"varius. Nam porttitor scelerisque neque.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2101,4,"sollicitudin a, malesuada id, erat. Etiam vestibulum");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2201,3,"Sed congue, elit sed");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2301,2,"sagittis felis. Donec tempor, est ac mattis semper, dui lectus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2401,1,"ut aliquam iaculis, lacus pede sagittis augue,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2501,5,"at pretium aliquet, metus urna convallis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2601,3,"amet risus. Donec egestas.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2701,6,"pede. Cras vulputate velit");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2801,1,"mattis semper, dui lectus rutrum urna, nec luctus felis purus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (2901,2,"nec");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3001,1,"amet metus. Aliquam erat");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3101,3,"justo.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3201,3,"nec ante. Maecenas mi felis,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3301,1,"mi tempor lorem, eget mollis lectus pede");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3401,4,"non, hendrerit id, ante. Nunc mauris sapien, cursus in,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3501,3,"ullamcorper magna. Sed eu eros. Nam consequat");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3601,1,"in");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3701,2,"Nam ac nulla. In tincidunt congue turpis. In condimentum.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3801,1,"viverra. Donec tempus, lorem fringilla ornare placerat, orci lacus vestibulum");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (3901,4,"eget ipsum.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4001,6,"tempor diam");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4101,6,"turpis non enim. Mauris quis turpis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4201,3,"ac facilisis facilisis, magna tellus faucibus leo, in lobortis tellus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4301,3,"pharetra nibh.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4401,2,"nibh. Donec est mauris, rhoncus id, mollis nec,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4501,5,"id nunc interdum");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4601,6,"lorem tristique aliquet. Phasellus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4701,3,"orci lacus vestibulum lorem, sit amet");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4801,1,"nulla. Donec non justo. Proin non");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (4901,5,"consectetuer");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5001,3,"sed,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5101,4,"Quisque fringilla euismod enim. Etiam gravida molestie arcu. Sed eu");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5201,5,"dolor. Fusce mi lorem,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5301,3,"venenatis vel, faucibus id, libero. Donec consectetuer");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5401,4,"vitae semper egestas, urna justo faucibus lectus, a sollicitudin");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5501,5,"blandit viverra. Donec tempus, lorem fringilla ornare");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5601,4,"tincidunt pede ac urna. Ut tincidunt vehicula");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5701,2,"eu enim. Etiam imperdiet dictum magna. Ut tincidunt orci quis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5801,6,"augue");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (5901,4,"sapien imperdiet ornare. In faucibus. Morbi vehicula. Pellentesque");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6001,3,"lacus. Aliquam rutrum");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6101,3,"non sapien molestie orci tincidunt adipiscing. Mauris molestie pharetra");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6201,6,"at pretium aliquet, metus urna convallis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6301,3,"tincidunt adipiscing. Mauris molestie pharetra nibh. Aliquam ornare, libero at");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6401,1,"Phasellus at augue id ante dictum cursus.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6501,3,"et, eros. Proin ultrices.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6601,1,"molestie tortor nibh sit amet orci. Ut sagittis lobortis mauris.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6701,1,"laoreet lectus quis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6801,5,"dictum eleifend, nunc");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (6901,6,"sagittis. Duis gravida. Praesent eu nulla at sem molestie");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7001,1,"quis, tristique ac,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7101,3,"ut, sem. Nulla interdum. Curabitur dictum. Phasellus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7201,5,"metus facilisis lorem tristique aliquet. Phasellus");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7301,3,"dignissim pharetra. Nam ac nulla. In tincidunt congue turpis.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7401,5,"pede. Cum sociis natoque penatibus et magnis dis parturient");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7501,6,"Vestibulum ante ipsum primis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7601,5,"nascetur ridiculus mus. Donec");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7701,2,"a, arcu. Sed et libero.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7801,4,"posuere at, velit.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (7901,1,"lorem");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8001,2,"lacus. Nulla tincidunt,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8101,4,"massa rutrum magna. Cras convallis convallis dolor. Quisque");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8201,5,"mus. Proin vel nisl. Quisque fringilla");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8301,4,"justo faucibus lectus, a sollicitudin orci sem eget massa. Suspendisse");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8401,2,"amet massa. Quisque porttitor eros nec");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8501,4,"massa non ante bibendum ullamcorper.");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8601,2,"Curabitur sed");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8701,6,"lorem, vehicula et, rutrum");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8801,6,"euismod");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (8901,2,"amet,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9001,3,"arcu imperdiet ullamcorper. Duis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9101,5,"Donec vitae erat vel pede blandit congue. In scelerisque scelerisque");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9201,5,"Cras lorem lorem, luctus ut, pellentesque eget,");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9301,2,"gravida sagittis. Duis");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9401,5,"erat eget ipsum. Suspendisse sagittis. Nullam");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9501,6,"Mauris");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9601,4,"a sollicitudin orci sem eget");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9701,4,"nonummy ultricies ornare, elit elit");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9801,1,"pede sagittis augue, eu");
INSERT INTO `messages` (`message_id`,`thread_id`,`message`) VALUES (9901,5,"posuere vulputate, lacus. Cras interdum. Nunc");

Answer 1

You could use sql union and append all single queries with their limits

$sql = "";
$threadsArray = explode($threads, ',');
foreach($threadArray as $key=>$value){
    $sql .= "(SELECT * FROM messages WHERE thread_id = {$value} LIMIT 10)";

    if ($key != (count($threadsArray) - 1)) $sql .= " UNION "; // Append union expect for last element
}

// Execute your query and filter the results to group messages from each thread

Answer 2

If this were not mysql, the obvious solution would be to use one of the SQL aggregate window functions. Given the mysql constraint, this article on the "explodybits" blog seems to show a somewhat effective work-around for getting mysql to emulate them. The summation of the article seems to be roughly the code below.

select * from (
    select @row_num := IF(@prev_value=m.thread_id,@row_num+1,1) AS RowNumber, 
           m.*,
           @prev_value := m.thread_id
    from messages m,
         (SELECT @row_num := 1) x,
         (SELECT @prev_value := 0) y
    where thread_id in (1,2,3)
    order by thread_id
) t1 where RowNumber <= 10;