sql GROUP_CONCAT(... SEPARATOR)

SELECT post.ID, post.User_id, post.Title, GROUP_CONCAT( tag.Tag_value

SEPARATOR ';' ) AS tags

FROM post

RIGHT JOIN tags_con_id ON tags_con_id.Post_ID = post.ID

LEFT JOIN tag ON tag.Tag_id = tags_con_id.Tag_id

GROUP BY post.ID

LIMIT 0 , 30 









--

-- 表的结构 `post`

--



CREATE TABLE `post` (

  `ID` int(11) NOT NULL,

  `Title` varchar(20) NOT NULL,

  `User_id` varchar(20) NOT NULL,

  `data` varchar(20) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;



--

-- 导出表中的数据 `post`

--



INSERT INTO `post` (`ID`, `Title`, `User_id`, `data`) VALUES

(1, 'title1', '1', '2012-10-25'),

(2, 'test2', '1', '2012-10-25');



-- --------------------------------------------------------



--

-- 表的结构 `tag`

--



CREATE TABLE `tag` (

  `Tag_id` int(11) NOT NULL,

  `Tag_value` varchar(20) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--

-- 导出表中的数据 `tag`

--

INSERT INTO `tag` (`Tag_id`, `Tag_value`) VALUES

(1, 'Tag1'),

(2, 'Tag2'),

(3, 'Tag3'),

(4, 'Tag4'),

(5, 'Tag5'),

(6, 'Tag6'),

(7, 'Tag7'),

(8, 'Tag8');



-- --------------------------------------------------------



--

-- 表的结构 `tags_con_id`

--



CREATE TABLE `tags_con_id` (

  `ID` int(11) NOT NULL,

  `Post_ID` int(11) NOT NULL,

  `Tag_id` int(11) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;



--

-- 导出表中的数据 `tags_con_id`

--



INSERT INTO `tags_con_id` (`ID`, `Post_ID`, `Tag_id`) VALUES

(1, 1, 1),

(2, 1, 2),

(3, 1, 3),

(4, 2, 4),

(5, 2, 5),

(6, 2, 6),

(7, 2, 7);