sqlserver如何把查询的某个字段的列表转换为字符串输出

代码如下：

declare @test varchar(max)
set @test=''
IF EXISTS(SELECT iid FROM  sort WHERE Parent=0)
begin
	select @test=@test+','+CAST(iid AS VARCHAR) from sort WHERE Parent=0 ORDER BY iid
	IF(LEN(@test)>0)
	begin
		SET @test=RIGHT(@test,LEN(@test)-1)
	END 
END 
select @test