只要你在建表时给列加了注释，下面的语句就可以实现你的要求。
Oracle:
select comments
from user_col_comments
where table_name = 'TEST'
and column_name = 'NAME';
from user_col_comments
where table_name = 'TEST'
and column_name = 'NAME';
SQL Server 2005:
SELECT a.NAME ,b.NAME,c.value
FROM sysobjects AS a
LEFT JOIN syscolumns AS b
ON a.id =b.id
LEFT JOIN sys.extended_properties AS c
ON b.id = c.major_id AND b.colid = c.minor_id
WHERE a.NAME ='表名'
FROM sysobjects AS a
LEFT JOIN syscolumns AS b
ON a.id =b.id
LEFT JOIN sys.extended_properties AS c
ON b.id = c.major_id AND b.colid = c.minor_id
WHERE a.NAME ='表名'
