1、批量修改表前缀

# def是现在的表前缀，abc是要修改成的表前缀 substring(table_name, 5)  5需要根据实际调整

SELECT
    CONCAT(
        'ALTER TABLE ',
        table_name,
        ' RENAME TO abc_',
        substring(table_name, 5),
        ';'
    ) sqls
FROM
    information_schema.tables Where table_name LIKE 'def_%';

2、批量修改表编码

SELECT 
CONCAT("ALTER TABLE `", TABLE_NAME,"` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;") 
AS target_tables
FROM INFORMATION_SCHEMA.TABLES

3、数据查重

select 字段名,count(id) as count from 数据库 group by 字段名 having count>1