MySQL批量修改表及表内字段排序规则举例详解

SELECT CONCAT('ALTER TABLE ', TABLE_SCHEMA, '.', TABLE_NAME,
              ' COLLATE utf8mb4_general_ci;') AS '修正SQL'
from information_schema.tables
where TABLE_SCHEMA = '数据库名'
  and TABLE_COLLATION = 'utf8mb4_german2_ci';

ALTER TABLE 数据库名.表名 COLLATE utf8mb4_general_ci;

SELECT
    CONCAT('ALTER TABLE `', table_name, '` MODIFY `', column_name, '` ', DATA_TYPE,
        '(', CHARACTER_MAXIMUM_LENGTH, ') CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci',
        (CASE WHEN IS_NULLABLE = 'NO' THEN ' NOT NULL' ELSE '' END),
        (case when IFNULL(column_comment,'')='' then '' else concat(' COMMENT \'' , column_comment ,'\'') end),
        ';') AS `修正SQL`
FROM information_schema.COLUMNS
WHERE 1=1
    and TABLE_SCHEMA = '数据库名' #要修改的数据库名称
    and DATA_TYPE IN ('varchar','char')
    and COLLATION_NAME='utf8mb4_german2_ci'

ALTER TABLE `t_categories` MODIFY `code` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '标识';

SELECT
    TABLE_SCHEMA '数据库',
    TABLE_NAME '表',
    COLUMN_NAME '字段',
    CHARACTER_SET_NAME '原字符集',
    COLLATION_NAME '原排序规则',
    CONCAT( 'ALTER TABLE ', TABLE_SCHEMA, '.', TABLE_NAME, ' MODIFY COLUMN ', COLUMN_NAME, ' ', COLUMN_TYPE, ' CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;' ) '修正SQL' 
FROM
    information_schema.`COLUMNS` 
WHERE
    COLLATION_NAME RLIKE 'utf8';

SELECT
    TABLE_SCHEMA '数据库',
    TABLE_NAME '表',
    TABLE_COLLATION '原排序规则',
    CONCAT( 'ALTER TABLE ', TABLE_SCHEMA, '.', TABLE_NAME, ' COLLATE=utf8mb4_general_ci;' ) '修正SQL' 
FROM
    information_schema.`TABLES` 
WHERE
    TABLE_COLLATION RLIKE 'utf8';

#修改数据库
SELECT
    SCHEMA_NAME '数据库',
    DEFAULT_CHARACTER_SET_NAME '原字符集',
    DEFAULT_COLLATION_NAME '原排序规则',
    CONCAT( 'ALTER DATABASE ', SCHEMA_NAME, ' CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;' ) '修正SQL' 
FROM
    information_schema.`SCHEMATA` 
WHERE
    DEFAULT_CHARACTER_SET_NAME RLIKE 'utf8';