(请参阅我在本文底部测试的数据库结构。)
我执行此查询:
SELECT m.title, GROUP_CONCAT(DISTINCT(d.name) SEPARATOR ',') d FROM movies m
INNER JOIN movies_seen s
ON s.object_id = m.id
LEFT JOIN movies_directors_connections dc
ON dc.movie_id = m.id
LEFT JOIN movies_directors d
ON d.id = dc.director_id
结果如下:
title | d
Pulp Fiction | Quentin Tarantino,George Butler,Robert Fiore
但我想要得到这个:
title | d
Pulp Fiction | Quentin Tarantino
Pumping Iron | George Butler,Robert Fiore
和建议? :)
CREATE TABLE `movies` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`title` varchar(90) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 ;
CREATE TABLE `movies_seen` (
`object_id` int(10) NOT NULL DEFAULT '0',
`date` varchar(10) NOT NULL DEFAULT '0');
CREATE TABLE `movies_directors` (
`id` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=4 ;
CREATE TABLE IF NOT EXISTS `movies_directors_connections` (
`movie_id` mediumint(8) unsigned NOT NULL DEFAULT '0',
`director_id` mediumint(8) unsigned NOT NULL DEFAULT '0'
) ENGINE=MyISAM;
然后是一些测试数据:
INSERT INTO `movies` (`id`, `title`) VALUES
(1, 'Pulp Fiction'), (2, 'Pumping Iron');
INSERT INTO `movies_seen` (`object_id`, `date`) VALUES
(1, 1359511222), (2, 1359511223);
INSERT INTO `movies_directors` (`id`, `name`) VALUES
(1, 'Quentin Tarantino'),
(2, 'George Butler'),
(3, 'Robert Fiore');
INSERT INTO `movies_directors_connections` (`movie_id`, `director_id`) VALUES
(1, 1), (2, 2), (2, 3);
答案 0 :(得分:7)
您只需要添加GROUP BY
子句
SELECT m.title,
GROUP_CONCAT(DISTINCT(d.name) SEPARATOR ',') d
FROM movies m
INNER JOIN movies_seen s
ON s.object_id = m.id
LEFT JOIN movies_directors_connections dc
ON dc.movie_id = m.id
LEFT JOIN movies_directors d
ON d.id = dc.director_id
GROUP BY m.title
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