--> 测试数据: @T
declare @T table (col1 int,col2 varchar(1),col3 int)
insert into @T
select 1,'a',11 union all
select 2,'b',12 union all
select 3,'c',13 union all
select 4,'d',14

--一行数据用逗号拼接
DECLARE @d VARCHAR(20)
SELECT  @d = LTRIM(col1) + ',' + col2 + ',' + LTRIM(col3)
FROM    @T
WHERE   col1 = 1
SELECT  @d
/*
1,a,11
*/

--一列数据用逗号拼接
DECLARE @d1 VARCHAR(20)
SET @d1 = ''
SELECT  @d1 = @d1 + col2 + ','
FROM    @T 
SELECT  LEFT(@d1, LEN(@d1) - 1)
/*
a,b,c,d
*/