查询字段的默认值

--使用在SQL2008,***查询字段说明和默认值
select   object_name(c.id) as 表名   ,c.name as 字段名   ,t.name as 数据类型   ,c.prec as 长度   ,
p.value as 字段说明   ,m.text as 默认值  
from syscolumns c   inner join   systypes t   on c.xusertype=t.xusertype   
left join  sys.extended_properties p   on c.id=p.major_id and c.colid = p.minor_id   
left join   syscomments m   on c.cdefault=m.id
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select * from sys.extended_properties  --SQL2008 扩展属性表（字段注释，）


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/*在sql2000中使用*/

--获取所有默认值：

select   object_name(c.id) as 表名   ,c.name as 字段名   ,t.name as 数据类型   ,c.prec as 长度   ,
p.value as 字段说明   ,m.text as 默认值  from syscolumns c   
inner join   systypes t   on c.xusertype=t.xusertype   
left join    sysproperties p   on c.id=p.id and c.colid = p.smallid   
left join   syscomments m   on c.cdefault=m.id

--获取单个字段默认值：

select   object_name(c.id) as 表名   ,c.name as 字段名   ,t.name as 数据类型   ,c.prec as 长度   ,
p.value as 字段说明   ,m.text as 默认值  from syscolumns c   
inner join   systypes t   on c.xusertype=t.xusertype   
left join    sysproperties p   on c.id=p.id and c.colid = p.smallid   
left join   syscomments m   on c.cdefault=m.id  
where objectproperty(c.id,'IsUserTable')=1   and object_name(c.id) = '表名' and c.name = '字段名称'  




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--查询指定表的指定字段的默认值
select   object_name(c.id) as 表名   ,c.name as 字段名   ,t.name as 数据类型   ,c.prec as 长度   ,
p.value as 字段说明   ,m.text as 默认值  from syscolumns c   
inner join   systypes t   on c.xusertype=t.xusertype   
left join  sys.extended_properties p   on c.id=p.major_id and c.colid = p.minor_id    
left join   syscomments m   on c.cdefault=m.id  
where objectproperty(c.id,'IsUserTable')=1   and object_name(c.id) = '表名' and c.name = '字段名'