SQL语句判断某列是否是主键

SELECT COUNT(1) AS Is_PK 
FROM  syscolumns  
JOIN  sysindexkeys 
    ON   syscolumns.id=sysindexkeys.id  AND  syscolumns.colid=sysindexkeys.colid   
JOIN  sysindexes  
    ON   syscolumns.id=sysindexes.id  AND  sysindexkeys.indid=sysindexes.indid  
JOIN  sysobjects  
    ON   sysindexes.name=sysobjects.name  AND  sysobjects.xtype='PK'
WHERE syscolumns.name=COLUMN_NAME AND syscolumns.id=object_id(Table_name)



完整代码：

SELECT a.Table_schema as 架构 ,a.Table_name as 表名   ,b.COLUMN_NAME as 栏位名称,b.DATA_TYPE  as 数据类型,isnull(b.CHARACTER_MAXIMUM_LENGTH,'')  as 长度  
,COLUMNPROPERTY(OBJECT_ID(a.Table_name), b.COLUMN_NAME, 'IsIdentity')  as 标识列,
(
    select   count(1)  from   syscolumns  
    join   sysindexkeys on   syscolumns.id=sysindexkeys.id   and   syscolumns.colid=sysindexkeys.colid   
    join   sysindexes  on   syscolumns.id=sysindexes.id   and   sysindexkeys.indid=sysindexes.indid  
    join   sysobjects  on   sysindexes.name=sysobjects.name   and   sysobjects.xtype='PK'
    WHERE syscolumns.name=b.COLUMN_NAME AND     syscolumns.id=object_id(a.Table_name )
) as 主键
       ,isnull(b.COLUMN_DEFAULT,'')   as 预设值   
       ,b.IS_NULLABLE  as 是否允许空值   
       ,( SELECT value 
          FROM fn_listextendedproperty (NULL, 'schema', a.Table_schema, 'table', a.TABLE_NAME, 'column', default)   
          WHERE name='MS_Description' and objtype='COLUMN'and objname Collate Chinese_Taiwan_Stroke_CI_AS = b.COLUMN_NAME   
        ) as 栏位备注   
FROM INFORMATION_SCHEMA.TABLES  a   
LEFT JOIN INFORMATION_SCHEMA.COLUMNS b    
     ON a.TABLE_NAME = b.TABLE_NAME   
ORDER BY a.TABLE_NAME, b.ORDINAL_POSITION  

GO