mysql加入csv字段? [英] mysql join on csv field?

问题描述

我有三个如下表

http://sqlfiddle.com/#!2/82212/6 :

CREATE TABLE IF NOT EXISTS `cat` (
  `id` int(15) NOT NULL AUTO_INCREMENT,
  `color_options` varchar(255) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
);
INSERT INTO `cat` (`id`, `color_options`) VALUES (1, '1,2,3,4');


CREATE TABLE IF NOT EXISTS `template` (
  `id` int(15) NOT NULL AUTO_INCREMENT,
  `cat_id` int(15) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
);

INSERT INTO `template` (`id`, `cat_id`) VALUES (1, 1);


CREATE TABLE IF NOT EXISTS `color` (
  `id` int(15) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL DEFAULT '',
  `code` varchar(6) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
);

INSERT INTO `color` (`id`, `name`, `code`) VALUES
(1, 'Black', '000000'),
(2, 'Red', 'FF0000'),
(3, 'Blue', '0000FF'),
(4, 'Green', '00FF00');

如果我运行

SELECT * 
FROM template
LEFT JOIN cat ON cat.id=template.id;

那我会得到

id  cat_id  color_options

1   1   1,2,3,4

如何获取文本(黑色，红色，蓝色，绿色)中的颜色选项而不是纯数字?

How do I get the color options in text(Black,Red,BLue,Green) instead of plain numbers?

我尝试使用连接，但不适用于csv字段.

I tried using join but it doesn't work on csv field.

预先感谢

推荐答案

带有GROUP_CONCAT()的子查询

A sub query with GROUP_CONCAT()

SELECT *,(SELECT GROUP_CONCAT(name) FROM color WHERE CONCAT(',',cat.color_options,',') LIKE CONCAT('%,',color.id,',%')) color_options_text
FROM template
LEFT JOIN cat ON cat.id=template.id

其他人对我来说使用了新功能，这也可以使用&读起来更干净

Someone else used a function new to me, this also works & is cleaner to read

SELECT *,(SELECT GROUP_CONCAT(name) FROM color WHERE FIND_IN_SET(color.id,cat.color_options)) color_options_text
FROM template
LEFT JOIN cat ON cat.id=template.id

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