求结果集转为字符串的方法

[linkinwhite]

比如有语句select username from Employee

返回结果是：
username
张三
李四
王五

怎么输出一个字符串类似：
张三，李四，王五

[--小F--]

declare @s varchar(1000)
select @s=isnull(@s+',','')+username from Employee
select @s as username

[行者_]

好了，这么多大牛回答你的问题了。

[百年树人]

declare @s varchar(1000)
select @s=isnull(@s+',','')+username from Employee
select @s as username

[htl258_Tony]

--------------------------------------------------------------------------
--  Author : htl258(Tony)
--  Date   : 2010-03-31 00:38:11
--  Version:Microsoft SQL Server 2008 (RTM) - 10.0.1600.22 (Intel X86) 
--          Jul  9 2008 14:43:34 
--          Copyright (c) 1988-2008 Microsoft Corporation
--          Developer Edition on Windows NT 5.1 <X86> (Build 2600: Service Pack 2)
--------------------------------------------------------------------------
--> 生成测试数据表:Employee

IF NOT OBJECT_ID('[Employee]') IS NULL
	DROP TABLE [Employee]
GO
CREATE TABLE [Employee]([username] NVARCHAR(10))
INSERT [Employee]
SELECT N'张三' UNION ALL
SELECT N'李四' UNION ALL
SELECT N'王五'
GO
--SELECT * FROM [Employee]

-->SQL查询如下:

DECLARE @S VARCHAR(100)
SELECT @S=ISNULL(@S+',','')+[username] FROM [Employee]
PRINT @S
--RESULT:
--张三,李四,王五

[永生天地]

sql版这类问题最多
[Quote=引用 1 楼 josy 的回复:]
SQL code
declare @s varchar(1000)
select @s=isnull(@s+',','')+username from Employee
select @s as username
[/Quote]