mysql获取所有的表结构及备注

根据库名导出所有表信息：

SELECT
    *
FROM
    information_schema.`TABLES`
WHERE
    TABLE_SCHEMA = 'db_name'

根据库名导出所有表名及表备注：

SELECT
    TABLE_NAME,
    TABLE_COMMENT
FROM
    information_schema.`TABLES`
WHERE
    TABLE_SCHEMA = 'db_name';

mysql获取整个库的所有表，及表结构：

SELECT
    TABLE_SCHEMA AS '库名',
    TABLE_NAME AS '表名',
    COLUMN_NAME AS '列名',
    ORDINAL_POSITION AS '列的排列顺序',
    COLUMN_DEFAULT AS '默认值',
    IS_NULLABLE AS '是否为空',
    DATA_TYPE AS '数据类型',
    CHARACTER_MAXIMUM_LENGTH AS '字符最大长度',
    NUMERIC_PRECISION AS '数值精度(最大位数)',
    NUMERIC_SCALE AS '小数精度',
    COLUMN_TYPE AS '列类型',
    COLUMN_KEY 'KEY',
    EXTRA AS '额外说明',
    COLUMN_COMMENT AS '注释'
FROM
    information_schema.`COLUMNS`
WHERE
    TABLE_SCHEMA = 'db_name'
ORDER BY
    TABLE_NAME,
    ORDINAL_POSITION;