Изменить кодировку всех таблиц

SELECT CONCAT('ALTER TABLE `', t.`TABLE_SCHEMA`, '`.`', t.`TABLE_NAME`, '` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;') as sqlcode
  FROM `information_schema`.`TABLES` t
WHERE 1
  AND t.`TABLE_SCHEMA` = 'db_name'
ORDER BY 1

ALTER TABLE `db_name`.`group_permissions` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
ALTER TABLE `db_name`.`group` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
ALTER TABLE `db_name`.`message` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;
....