如何得到一个字段的默认值？

syscolumns中有一个字段是cdefault好像是默认值对象的ID，再如何进一步得到具体的值呢？
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select text from syscomments
where id =
(select cdefault from syscolumns
where id = object_id('表名') and name = '字段名')
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SELECT text
FROM syscomments
WHERE id =
(SELECT Cdefault
FROM syscolumns
WHERE id = object_id('YourTableName' AND name = 'YourColName'))