MySQL 匈牙利字符的 ORDER BY 错误答案

【问题标题】：MySQL wrong ORDER BY for hungarian charactersMySQL 匈牙利字符的 ORDER BY 错误
【发布时间】：2019-08-19 11:20:14
【问题描述】：

我运行以下查询：

SELECT name FROM shops ORDER BY name;

当前结果：

ABC shop
ÁDE shop
ALT shop

预期结果应该是：

ABC shop
ALT shop
ÁDE shop

看起来A 和Á 是相等的。（正确顺序：a

我尝试使用匈牙利排序规则（使用 mysql 8.0.17）：

ALTER DATABASE mydb CHARACTER SET utf8mb4 COLLATE utf8mb4_hu_0900_ai_ci;

我发现 mysql 团队已经在 mysql 8.0.1 中修复了这个问题：https://bugs.mysql.com/bug.php?id=12519

SHOW CREATE TABLE 商店；

| shops | CREATE TABLE `shops` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `address_id` bigint(20) unsigned DEFAULT NULL,
  `shop_category_id` bigint(20) unsigned DEFAULT NULL,
  `shop_chain_id` bigint(20) unsigned DEFAULT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  `partner_id` bigint(20) unsigned DEFAULT NULL,
  `location_id` bigint(20) unsigned DEFAULT NULL,
  `is_active` tinyint(1) NOT NULL DEFAULT '1',
  `user_id` bigint(20) unsigned DEFAULT NULL,
  `deputy_user_id` bigint(20) unsigned DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `shops_address_id_foreign` (`address_id`),
  KEY `shops_shop_category_id_foreign` (`shop_category_id`),
  KEY `shops_shop_chain_id_foreign` (`shop_chain_id`),
  KEY `shops_partner_id_foreign` (`partner_id`),
  KEY `shops_location_id_foreign` (`location_id`),
  KEY `shops_user_id_foreign` (`user_id`),
  KEY `shops_deputy_user_id_foreign` (`deputy_user_id`),
  CONSTRAINT `shops_address_id_foreign` FOREIGN KEY (`address_id`) REFERENCES `addresses` (`id`) ON DELETE SET NULL,
  CONSTRAINT `shops_deputy_user_id_foreign` FOREIGN KEY (`deputy_user_id`) REFERENCES `users` (`id`) ON DELETE SET NULL,
  CONSTRAINT `shops_location_id_foreign` FOREIGN KEY (`location_id`) REFERENCES `locations` (`id`) ON DELETE SET NULL,
  CONSTRAINT `shops_partner_id_foreign` FOREIGN KEY (`partner_id`) REFERENCES `partners` (`id`) ON DELETE CASCADE,
  CONSTRAINT `shops_shop_category_id_foreign` FOREIGN KEY (`shop_category_id`) REFERENCES `shop_categories` (`id`) ON DELETE SET NULL,
  CONSTRAINT `shops_shop_chain_id_foreign` FOREIGN KEY (`shop_chain_id`) REFERENCES `shop_chains` (`id`) ON DELETE SET NULL,
  CONSTRAINT `shops_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB AUTO_INCREMENT=564 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_hu_0900_ai_ci

【问题讨论】：

看看定制订购：stackoverflow.com/questions/4768594/…
@Strawberry 问题已更新。
@BrettGregson 这个自定义排序看起来有点老套，但我会试试的
为什么是 PHP 标签？您的问题与此无关，除非您想在 PHP 中进行排序。
@Peter Kota 不是专家，但它不是 utf8mb4_hu_0900_as_cs 区分重音和大小写的.. 所以它对待

标签： mysql sql character-encoding special-characters collation

【解决方案1】：

没有简单的解决方案：

计划 A：编写自己的排序规则。

B 计划：在 bugs.mysql.com 上写一个错误，抱怨即使在 8.0.17 中，utf8mb4_hu_0900_ai_ci 也是“不正确的”。

（同时，我怀疑 utf8mb4_hungarian_ci 保留了 5.7 排序规则以实现向后兼容性。）

【讨论】：

我看到了您对错误报告的评论；但匈牙利排序规则本身似乎很模棱两可。回顾第一条评论，其中定义了“规则”，它说：“一般来说，在排序或比较时，短版和长版应该被同等对待，除非顺序不能由后面的字符决定元音。”
很难想象这在 mysql 中不起作用。创建自己的排序规则听起来很棒。我会试试。谢谢@RickJames

【解决方案2】：

问题本身是错误的。预期结果是：

ABC shop
ÁDE shop
ALT shop

没错。

https://helyesiras.mta.hu/helyesiras/default/akh12#F2_4

【讨论】：