批量修改库结构，表结构，表字段的字符集和排序规则

-- 获取所有以"aurora"开头的库中的信息
SELECT 
  SCHEMA_NAME 
FROM 
  information_schema.SCHEMATA 
WHERE 
  SCHEMA_NAME LIKE 'aurora%';

-- 生成修改库结构的脚本
SELECT 
  CONCAT(
    'ALTER DATABASE ', 
    SCHEMA_NAME, 
    ' CHARACTER SET utf8 COLLATE utf8_general_ci;'
  ) AS DATABASE_SQL_SCRIPT
FROM 
  information_schema.SCHEMATA 
WHERE 
  SCHEMA_NAME LIKE 'aurora%';

-- 获取所有以"aurora"开头的库中的表的信息
SELECT 
  TABLE_NAME, 
  TABLE_SCHEMA 
FROM 
  information_schema.TABLES 
WHERE 
  TABLE_SCHEMA LIKE 'aurora%';

-- 生成修改表结构的脚本
SELECT 
  CONCAT(
    'ALTER TABLE ', 
    TABLE_SCHEMA, '.', 
    TABLE_NAME, 
    ' CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;'
  ) AS TABLE_SQL_SCRIPT
FROM 
  information_schema.TABLES 
WHERE 
  TABLE_SCHEMA LIKE 'aurora%';

-- 获取所有以"aurora"开头的库中的字符串类型字段的信息
SELECT 
  TABLE_NAME, 
  COLUMN_NAME, 
  DATA_TYPE, 
  CHARACTER_MAXIMUM_LENGTH, 
  IS_NULLABLE, 
  COLUMN_DEFAULT, 
  COLUMN_COMMENT,
  TABLE_SCHEMA
FROM 
  information_schema.COLUMNS 
WHERE 
  TABLE_SCHEMA LIKE 'aurora%' 
  AND DATA_TYPE IN ('varchar', 'char', 'tinytext', 'text', 'mediumtext', 'longtext');

-- 生成修改表字段的脚本
SELECT 
  CONCAT(
    'ALTER TABLE ', 
    TABLE_SCHEMA, '.', 
    TABLE_NAME, 
    ' MODIFY ', 
    COLUMN_NAME, ' ', 
    IF(CHARACTER_MAXIMUM_LENGTH IS NULL OR DATA_TYPE IN ('longtext', 'text'), DATA_TYPE, CONCAT(DATA_TYPE, '(', CHARACTER_MAXIMUM_LENGTH, ')')), 
    ' CHARACTER SET utf8 COLLATE utf8_general_ci', 
    IF(IS_NULLABLE = 'NO', ' NOT NULL', ''), 
    IF(COLUMN_DEFAULT IS NOT NULL AND COLUMN_DEFAULT != '', CONCAT(' DEFAULT ', QUOTE(COLUMN_DEFAULT)), IF(COLUMN_DEFAULT IS NULL, '', ' DEFAULT ""')), 
    IF(COLUMN_COMMENT IS NOT NULL, CONCAT(' COMMENT "', COLUMN_COMMENT, '"'), ''), 
    ';'
  ) AS COLUMN_SQL_SCRIPT
FROM 
  information_schema.COLUMNS 
WHERE 
  TABLE_SCHEMA LIKE 'aurora%' 
  AND DATA_TYPE IN ('varchar', 'char', 'tinytext', 'text', 'mediumtext', 'longtext');