SQL获取数据库名，表名，列名，说明等信息

由于最近工作涉及SQL语句较多，对一些不常见的SQL函数、及存储过程下面进行整理和描述，供大家分享：

/**************************************************************************************************************
1、获取所有用户名:
islogin='1'   :表示帐户
islogin='0'   :表示角色
status='2'   :表示用户帐户
status='0'   :表示系统帐户
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SELECT name
FROM   sysusers
WHERE  status = ''
       AND islogin = ''
/**************************************************************************************************************
2、获取所有数据库名:
**************************************************************************************************************/
SELECT name
FROM     master..sysdatabases
ORDER BY name
/**************************************************************************************************************
3、获取所有表名:
XType='U'    :表示所有用户表;
XType='S'    :表示所有系统表;
**************************************************************************************************************/
SELECT name
FROM     数据库名..sysobjects
WHERE    xtype = 'U'
ORDER BY name
/**************************************************************************************************************
4、获取所有字段名:
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SELECT name
FROM   syscolumns
WHERE  id = Object_id('表名')
/**************************************************************************************************************
5、获取数据库所有类型:
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SELECT name
FROM   systypes
/**************************************************************************************************************
6、获取主键字段:
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SELECT name
FROM   syscolumns
WHERE  id = Object_id('表名')
       AND colid = (SELECT TOP 1 keyno
                    FROM   sysindexkeys
                    WHERE  id = Object_id('表名'))
/**************************************************************************************************************
7、获取表字段的基本信息:
a.
**************************************************************************************************************/
SELECT 字段名 = Rtrim(b.name)
       ,主键 = CASE
               WHEN h.id IS NOT NULL THEN 'PK'
               ELSE ''
             END
       ,字段类型 = Type_name(b.xusertype)
                + CASE
                    WHEN b.colstat & 1 = 1 THEN '[ID('
                                                 + CONVERT(VARCHAR,Ident_seed(a.name))
                                                 + ','
                                                 + CONVERT(VARCHAR,Ident_incr(a.name))
                                                 + ')]'
                    ELSE ''
                  END
       ,长度 = b.length
       ,允许空 = CASE b.isnullable
                WHEN 0 THEN 'N'
                ELSE 'Y'
              END
       ,默认值 = Isnull(e.TEXT,'')
       ,字段说明 = Isnull(c.VALUE,'')
FROM     sysobjects a
         INNER JOIN  sys.all_objects aa
           ON a.id=aa.object_id
              AND  schema_name(schema_id)='dbo'
         ,syscolumns b
         LEFT OUTER JOIN sys.extended_properties c
           ON b.id = c.major_id
              AND b.colid = c.minor_id
         LEFT OUTER JOIN syscomments e
           ON b.cdefault = e.id
         LEFT OUTER JOIN (SELECT g.id
                                 ,g.colid
                          FROM   sysindexes f
                                 ,sysindexkeys g
                          WHERE  (f.id = g.id)
                                 AND (f.indid = g.indid)
                                 AND (f.indid > 0)
                                 AND (f.indid < 255)
                                 AND (f.status & 2048) <> 0) h
           ON (b.id = h.id)
              AND (b.colid = h.colid)
WHERE    (a.id = b.id)
         AND (a.id = Object_id('表名'))  --要查询的表改成你要查询表的名称
ORDER BY b.colid
/**************************************************************************************************************
b.
**************************************************************************************************************/
SELECT 表名 = CASE
              WHEN a.colorder = 1 THEN d.name
              ELSE ''
            END
       ,表说明 = CASE
                WHEN a.colorder = 1 THEN Isnull(f.VALUE,'')
                ELSE ''
              END
       ,字段序号 = a.colorder
       ,字段名 = a.name
       ,标识 = CASE
               WHEN Columnproperty(a.id,a.name,'IsIdentity') = 1 THEN '√'
               ELSE ''
             END
       ,主键 = CASE
               WHEN EXISTS (SELECT 1
                            FROM   sysobjects
                            WHERE  xtype = 'PK'
                                   AND name IN (SELECT name
                                                FROM   sysindexes
                                                WHERE  indid IN (SELECT indid
                                                                 FROM   sysindexkeys
                                                                 WHERE  id = a.id
                                                                        AND colid = a.colid))) THEN '√'
               ELSE ''
             END
       ,类型 = b.name
       ,字段长度 = a.length
       ,占用字节数 = Columnproperty(a.id,a.name,'PRECISION')
       ,小数位数 = Isnull(Columnproperty(a.id,a.name,'Scale'),0)
       ,允许空 = CASE
                WHEN a.isnullable = 1 THEN '√'
                ELSE ''
              END
       ,默认值 = Isnull(e.TEXT,'')
       ,字段说明 = Isnull(g.[value],'')
FROM     syscolumns a
         LEFT JOIN systypes b
           ON a.xusertype = b.xusertype
         INNER JOIN sysobjects d
           ON (a.id = d.id)
              AND (d.xtype = 'U')
              AND (d.name <> 'dtproperties')
          INNER JOIN  sys.all_objects c
            ON d.id=c.object_id
                AND  schema_name(schema_id)='dbo'
         LEFT JOIN syscomments e
           ON a.cdefault = e.id
         LEFT JOIN sys.extended_properties g
           ON (a.id = g.major_id)
              AND (a.colid = g.minor_id)
         LEFT JOIN sys.extended_properties f
           ON (d.id = f.major_id)
              AND (f.minor_id = 0)
--where d.name='要查询的表'         --如果只查询指定表,加上此条件
ORDER BY a.id
         ,a.colorder
/***************************************************************************************************************
c. 前两种不完整~
****************************************************************************************************************/
-- 資料庫中所有資料表：透過內定的Stored Procedure sp_tables
EXEC sp_tables @table_name = '%',@table_owner = 'dbo',@table_qualifier = @DBName;
--    取得資料表Schema
EXEC sp_columns @TableName
--    取得欄位說明、備註(Extended Property)：這個是透過Sql內定的Function來處理
SELECT * FROM  ::fn_listextendedproperty(NULL, 'user', 'dbo', 'table', @TableName, 'column', default)
--    取得主索引
EXEC sp_pkeys @TableName 

/**************************************************************************************************************
表及字段描述信息处理示例
**************************************************************************************************************/

--创建表
CREATE TABLE 表 (
  a1  VARCHAR(10)
  ,a2 CHAR(2))
--为表添加描述信息
EXECUTE Sp_addextendedproperty N'MS_Description' , '人员信息表' , N'user' , N'dbo' , N'table' , N'表' , NULL , NULL
EXEC sys.sp_addextendedproperty
@name=N'MS_Description', @value=N'人员信息表' ,
@level0type=N'SCHEMA',@level0name=N'dbo',
@level1type=N'TABLE',@level1name=N'表'

--为字段a1添加描述信息
EXECUTE Sp_addextendedproperty N'MS_Description' , '姓名' , N'user' , N'dbo' , N'table' , N'表' , N'column' , N'a1'
EXEC sys.sp_addextendedproperty
@name=N'MS_Description', @value=N'人员信息表' ,
@level0type=N'SCHEMA',@level0name=N'dbo',
@level1type=N'TABLE',@level1name=N'表',
@level2type=N'COLUMN',@level2name=N'a1'

--为字段a2添加描述信息
EXECUTE Sp_addextendedproperty N'MS_Description' , '性别' , N'user' , N'dbo' , N'table' , N'表' , N'column' , N'a2'
--更新表中列a1的描述属性：
EXEC Sp_updateextendedproperty 'MS_Description' , '字段1' , 'user' , dbo , 'table' , '表' , 'column' , a1
--显示表的描述属性
SELECT *
FROM   ::fn_listextendedproperty(NULL,'user','dbo','table','表','column',NULL)
--删除表中列a1的描述属性：
EXEC Sp_dropextendedproperty 'MS_Description' , 'user' , dbo , 'table' , '表' , 'column' , a1
--删除测试
DROP TABLE 表