Question

i need to extract the last comment for each profile, for the last 100 profiles

each profile, if type==1, has at least 1 comment

• type==1 => is company
• type==2 => is human

Here are the relevant tables and data:

CREATE TABLE IF NOT EXISTS `comment` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `profile` int(11) NOT NULL,
  `name` varchar(200) NOT NULL,
  `email` varchar(200) NOT NULL,
  `county` int(11) NOT NULL,
  `comment` text NOT NULL,
  `created` int(11) NOT NULL,
  `status` int(11) NOT NULL,
  `verified` int(11) NOT NULL,
  UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;

INSERT INTO `comment` (`id`, `profile`, `name`, `email`, `county`, `comment`, `created`, `status`, `verified`) VALUES
(1, 1, 'ANGAJAT 1', 'email 2', 1, 'comm 1', 1335423985, 0, 0),
(2, 3, 'ANGAJAT 2', 'email 4', 1, 'comm 2', 1335424011, 0, 0),
(3, 5, 'ANGAJAT 3', 'email 6', 1, 'comm 3', 1335424037, 0, 0),
(4, 5, 'ANGAJAT 3', 'email 6', 1, 'comm 4', 1335424039, 0, 0);

CREATE TABLE IF NOT EXISTS `profile` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `type` int(11) NOT NULL COMMENT '1 = angajatori ; 2 - angajati',
  `name` varchar(200) NOT NULL,
  `county` int(11) NOT NULL,
  `email` varchar(200) NOT NULL,
  `created` int(11) NOT NULL,
  `comments` int(11) NOT NULL,
  `status` int(11) NOT NULL,
  `verified` int(11) NOT NULL,
  UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ;

INSERT INTO `profile` (`id`, `type`, `name`, `county`, `email`, `created`, `comments`, `status`, `verified`) VALUES
(1, 1, 'ANGAJATOR 1', 1, 'email 1', 1335423985, 0, 0, 0),
(2, 2, 'ANGAJAT 1', 1, 'email 2', 1335423985, 0, 0, 0),
(3, 1, 'ANGAJATOR 2', 1, 'email 3', 1335424011, 0, 0, 0),
(4, 2, 'ANGAJAT 2', 1, 'email 4', 1335424011, 0, 0, 0),
(5, 1, 'ANGAJATOR 3', 1, 'email 5', 1335424037, 0, 0, 0),
(6, 2, 'ANGAJAT 3', 1, 'email 6', 1335424037, 0, 0, 0);\

I tried :

SELECT * 
FROM COMMENT c
JOIN profile p ON p.id = c.profile
GROUP BY c.profile
ORDER BY c.created DESC , p.id ASC 
LIMIT 100

and I got :

id  profile name    email   county  comment created status  verified    id  type    name    county  email   created comments    status  verified
3   5   ANGAJAT 3   email 6 1   comm 3  1335424037  0   0   5   1   ANGAJATOR 3 1   email 5 1335424037  0   0   0
2   3   ANGAJAT 2   email 4 1   comm 2  1335424011  0   0   3   1   ANGAJATOR 2 1   email 3 1335424011  0   0   0
1   1   ANGAJAT 1   email 2 1   comm 1  1335423985  0   0   1   1   ANGAJATOR 1 1   email 1 1335423985  0   0   0

the query returns the first comment for the each 100 last companies

pls help with query

Answer 1

Try this:

SELECT c.* 
FROM COMMENT c
JOIN 
  (SELECT MAX(created_at) created_at, profile FROM COMMENT
   GROUP BY profile) p ON p.profile = c.profile AND p.created_at = c.created_at
ORDER BY c.created DESC , p.profile ASC 
LIMIT 100

It should do the trick.