MySQL：

       查看表注释：用 SHOW TABLE STATUS [FROM db_name]

              示例：

                       SHOW TABLE STATUS ； –数据库下所有表注释

                       SHOW TABLE STATUS FROM ‘dbname’; –数据库[dbname]下所有表注释

                       SHOW TABLE STATUS FROM ‘dbname’ WHERE NAME = ‘table’; –查看表[table]的注释

      查看字段注释：

              查询数据库 db_name 的 表 table_name 的字段信息：

                       select * from information_schema.columns T where table_schema =’db_name’ and table_name = ‘table_name’;

Oracle：

            查看表注释：

                SELECT * FROM USER_TAB_COMMENTS T WHERE T.TABLE_NAME=‘table_name’

                USER_TAB_COMMENTS ：table_name,table_type,comments

            查看字段注释：

                默认为当前连接数据库

                SELECT * FROM USER_COL_COMMENTS T WHERE T.TABLE_NAME=‘table_name’

                SELECT T.TABLE_NAME,T.COLUMN_NAME,T.COMMENTS FROM USER_COL_COMMENTS T WHERE T.TABLE_NAME=‘table_name’