我遵循这个问题的答案:MySQL:是否可以group_concat多行?
但是我在MySql错误中挣扎:
#1054 - Unknown column 'CM_Cocktail.id' in 'field list'
.
当我删除这个 CM_Cocktail.id 的东西时,下一个错误应用者:#1054 - Unknown column 'CM_Zutat.name' in 'field list'
.我尝试使用别名,但情况变得更糟...也许我是瞎子。
SELECT
CM_Cocktail.id, CM_Cocktail.name,
GROUP_CONCAT(CM_Zutat.name SEPARATOR ', ')
FROM (
SELECT CM_Cocktail.id, CM_Cocktail.name AS cname, CM_Zutat.name
FROM CM_Cocktail, CM_CocktailHatZutat, CM_Zutat
WHERE CM_Cocktail.id=CM_CocktailHatZutat.cocktail_id
AND CM_CocktailHatZutat.zutat_id=CM_Zutat.id
) group_attr
GROUP BY CM_Cocktail.id;
CREATE TABLE IF NOT EXISTS `CM_Cocktail` (
`id` int(3) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `name` (`name`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;
CREATE TABLE IF NOT EXISTS `CM_CocktailHatZutat` (
`cocktail_id` int(3) NOT NULL,
`zutat_id` int(3) NOT NULL,
`zutat_menge` int(4) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
CREATE TABLE IF NOT EXISTS `CM_Zutat` (
`id` int(3) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `name` (`name`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;
您需要
在子查询中定义列别名,然后使用别名作为父字段,如以下示例所示:
SELECT
CocktailID, cname,
GROUP_CONCAT(ZName SEPARATOR ', ')
FROM (
SELECT CM_Cocktail.id as CocktailID, CM_Cocktail.name AS cname, CM_Zutat.name as ZName
FROM CM_Cocktail, CM_CocktailHatZutat, CM_Zutat
WHERE CM_Cocktail.id=CM_CocktailHatZutat.cocktail_id
AND CM_CocktailHatZutat.zutat_id=CM_Zutat.id
) group_attr
GROUP BY CocktailID;
请尝试这个
SELECT
id, name,
GROUP_CONCAT(CM_Zutat.name SEPARATOR ', ')
FROM (
SELECT CM_Cocktail.id, CM_Cocktail.name AS cname, CM_Zutat.name
FROM CM_Cocktail, CM_CocktailHatZutat, CM_Zutat
WHERE CM_Cocktail.id=CM_CocktailHatZutat.cocktail_id
AND CM_CocktailHatZutat.zutat_id=CM_Zutat.id
) group_attr
GROUP BY id;
因为您使用子查询