執行

SELECT
	CONCAT( 'ALTER TABLE `', TABLE_SCHEMA, '`.`', TABLE_NAME, '`', ' CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;' ) AS sql_statements 
FROM
	information_schema.COLUMNS 
WHERE
	TABLE_SCHEMA = 'database_name' 
	AND CHARACTER_SET_NAME = 'utf8' 
	AND COLLATION_NAME LIKE '%utf8%' 
GROUP BY
	TABLE_NAME

請將 database_name 替換為要更改字符集的數據庫名稱。

然后運行上面SQL語句生成的所有SQL語句來更改表和列的字符集。