我有一个这样的数据库结构:
国家
CREATE TABLE IF NOT EXISTS `countries` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`code` varchar(2) COLLATE utf8_unicode_ci NOT NULL,
`is_active` tinyint(1) NOT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `UNIQ_5D66EBAD77153098` (`code`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
国家 语言
CREATE TABLE IF NOT EXISTS `country_languages` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`language_id` int(11) DEFAULT NULL,
`country_id` int(11) DEFAULT NULL,
`name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`),
KEY `IDX_1532561982F1BAF4` (`language_id`),
KEY `IDX_15325619F92F3E70` (`country_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
Language
CREATE TABLE IF NOT EXISTS `languages` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`iso` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
`active` tinyint(1) NOT NULL DEFAULT '1',
`is_primary` tinyint(1) DEFAULT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `UNIQ_A0D153795E237E06` (`name`),
UNIQUE KEY `UNIQ_A0D1537961587F41` (`iso`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
以及语言表的数据:
id name iso
----------------------
1 English en
2 German de
3 Italian it
和国家表:
id code
----------------
1 ie
和国家语言表
id country_id language_id name
----------------------------------------------
1 1 1 Ireland in English
2 1 2 Ireland in German
我正在尝试编写一个查询,该查询将返回以下结果以便能够显示它。 (如果可能的话)
(Language) (Country name)
English Ireland in English
German Ireland in German
Italian #NULL OR EMPTY STRING
其次,我试图了解是否可以将英语设置为默认语言,并且当 id 3(意大利语)的语言内容不存在时,默认值应该回退,结果如下:
(Language) (Country name)
English Ireland in English
German Ireland in German
Italian Ireland in English #please note language id is 3 -> Italian.