-- 获取用于添加表备注的 SQL 语句
SELECT
    CONCAT('ALTER TABLE 目标数据库名.', TABLE_NAME, ' COMMENT = \'', TABLE_COMMENT, '\';') AS alter_table_comment_sql
FROM
    INFORMATION_SCHEMA.TABLES
WHERE
    TABLE_SCHEMA = '源数据库名'
    AND TABLE_COMMENT IS NOT NULL;

-- 获取用于添加字段备注的 SQL 语句
SELECT
    CONCAT(
        'ALTER TABLE 目标数据库名.',
        TABLE_NAME,
        ' MODIFY COLUMN ',
        COLUMN_NAME,
        ' ',
        COLUMN_TYPE,
        CASE
            WHEN IS_NULLABLE = 'NO' THEN ' NOT NULL'
            ELSE ''
        END,
        CASE
            WHEN COLUMN_DEFAULT IS NOT NULL THEN ' DEFAULT ' ELSE ''
        END,
        IFNULL(COLUMN_DEFAULT, ''),
        ' COMMENT \'',
        COLUMN_COMMENT,
        '\';'
    ) AS alter_column_comment_sql
FROM
    INFORMATION_SCHEMA.COLUMNS
WHERE
    TABLE_SCHEMA = '源数据库名'
    AND COLUMN_COMMENT IS NOT NULL;