批量修改某个库下面，所有表字段的排序规则，执行下面的脚本

SELECT
    CONCAT(
        'ALTER TABLE `',table_name,'` MODIFY `',column_name,'` ',DATA_TYPE,'(',CHARACTER_MAXIMUM_LENGTH,') CHARACTER SET UTF8 COLLATE utf8_general_ci',(
            CASE
            WHEN IS_NULLABLE = 'NO' THEN
                ' NOT NULL'
            ELSE
                ''
            END
        ),';'
    )
FROM
    information_schema. COLUMNS
WHERE
    TABLE_SCHEMA = 'schema_name'
AND DATA_TYPE = 'varchar'
AND (
    CHARACTER_SET_NAME != 'utf8'
    OR COLLATION_NAME != 'utf8_general_ci'
);

将拿到的结果脚本再运行一次