Mysql：过滤表依赖于不同表中列的子字符串

Posted 2023-03-14

【中文标题】Mysql：过滤表依赖于不同表中列的子字符串

【英文标题】：Mysql: Filter table depend on subtring from column in different table

【发布时间】：2021-08-10 08:53:44

【问题描述】：

我的数据库中有 2 个表。

1- 客户表。

+-----------+--------------------------------+
| customers | CREATE TABLE `customers` (
  `id` int unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `phone` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  PRIMARY KEY (`id`),
  KEY `customers_phone_index` (`phone`)
) ENGINE=InnoDB AUTO_INCREMENT=42 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |
+-----------+--------------------------------+

===>客户表中的数据示例

+----+----------------------------------------+-----------------+
| id | name                                   | phone           |
+----+----------------------------------------+-----------------+
| 1  | Frehiwot Teka                          | (251) 988200000 |
| 2  | Fanetahune Abaia                       | (251) 924418461 |
| 3  | Yonatan Tekelay                        | (251) 911168450 |
| 4  | EMILE CHRISTIAN KOUKOU DIKANDA HONORE  | (237) 697151594 |
| 5  | MICHAEL MICHAEL                        | (237) 677046616 |
| 6  | ARREYMANYOR ROLAND TABOT               | (237) 6A0311634 |
|  7 | Edunildo Gomes Alberto                 | (258) 847651504 |
|  8 | Walla's Singz Junior                   | (258) 846565883 |
|  9 | sevilton sylvestre                     | (258) 849181828 |
+----+----------------------------------------+-----------------+

2- 国家/地区表。

+-----------+--------------------------------+
 countries | CREATE TABLE `countries` (
  `id` int unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(80) COLLATE utf8mb4_unicode_ci NOT NULL,
  `numcode` smallint DEFAULT NULL,
  `phonecode` int NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=254 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |
+-----------+--------------------------------+

===>国家表中的数据示例。

+----+----------------+---------+-----------+
| id | name           | numcode | phonecode |
+----+----------------+---------+-----------+
|  1 | Cameroon       |     120 |       237 |
|  2 | Ethiopia       |     231 |       251 |
|  3 | Mozambique     |     508 |       258 |
|  4 | American Samoa |      16 |      1684 |
|  5 | Andorra        |      20 |       376 |
|  6 | Angola         |      24 |       244 |
+-----+---------------+---------+-----------+

==> 我需要获取带有国家名称和代码的电话号码列表。

==> 输出示例

+------------+--------------+--------------+
| country    | country_code | phone_number |
+------------+--------------+--------------+
| Cameroon   | 237          |  6A0311634   |
| Cameroon   | 237          |  697151594   |
| Cameroon   | 237          |  677046616   |
| Ethiopia   | 251          |  924418461   |
| Ethiopia   | 251          |  911168450   |
| Mozambique | 258          |  849181828   |
| Mozambique | 258          |  847651504   |
| Mozambique | 258          |  846565883   |
+------------+--------------+--------------+

【问题讨论】：

您需要规范化您的数据，例如通过将电话号码中的国家代码移动到单独的列中。这将比在查询中使用regular expressions 容易得多，这会使查询执行得更慢。

.. FROM customers JOIN countries ON SUBSTRING_INDEX(SUBSTRING(phone FROM 2), ')', 1) = phonecode ..

【参考方案1】：

在 mysql 中，可以这样表达：

select c.*,
       co.country, substring_index(co.phone, ' ', -1) as phone_number
from customers c left join
     countries co
     on c.phone like concat('(', co.phone, ')%');