mysql 查询指定编码格式

-- 查询整个数据库的默认字符集和校对规则
SHOW VARIABLES LIKE 'character_set_database';
SHOW VARIABLES LIKE 'collation_database';

-- 查询特定表的字符集和校对规则
SHOW TABLE STATUS FROM `database_name` LIKE 'table_name';

-- 查询特定列的字符集和校对规则
SELECT CHARACTER_SET_NAME, COLLATION_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'database_name' AND TABLE_NAME = 'table_name' AND COLUMN_NAME = 'column_name';

CREATE TABLE `table_name` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

$mysqli = new mysqli("host", "user", "password", "database");
$mysqli->set_charset("utf8mb4");

ALTER TABLE `table_name` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;