IT忍者神龟之一句sql语句——连接同一字段的所有值

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Oracle可以用SYS_CONNECT_BY_PATH字符串聚合函数:
SELECT LTRIM(MAX(SYS_CONNECT_BY_PATH(productname, ‘, ‘)), ‘, ‘) AS productname
FROM(
    SELECT ‘1‘ as id, productname,
        ROW_NUMBER() OVER (PARTITION BY ‘1‘ ORDER BY productname) AS curr,
        ROW_NUMBER() OVER (PARTITION BY ‘1‘ ORDER BY productname) -1 AS prev
    FROM products
    -- where 条件
    order by productname
)
START WITH curr = 1
CONNECT BY prev = PRIOR curr AND id = PRIOR id
GROUP BY id

但MS SQL 2000没有这种函数,但可以通过自定义函数或过程来实现.
-- drop function ConnectString
Create FUNCTION ConnectString( @name varchar(20) ) 
RETURNS varchar(1024) 
AS 
BEGIN 
declare @Str varchar(1024) 
set @Str = ‘‘ 
select @Str = @Str + (case when @Str = ‘‘ then ‘‘ else ‘,‘ end) + [productname] from products 
--where [productname] = @name 
return @Str 
END 
GO

-- 调用
select DISTINCT dbo.ConnectString(productname) from products

SQL Server 2005 可用OUTER APPLY:
以下是从网上摘录的:
-- 示例数据
DECLARE @t TABLE(id int, value varchar(10))
INSERT @t SELECT 1, ‘aa‘
UNION ALL SELECT 1, ‘bb‘
UNION ALL SELECT 2, ‘aaa‘
UNION ALL SELECT 2, ‘bbb‘
UNION ALL SELECT 2, ‘ccc‘

-- 查询处理
SELECT *
FROM(
    SELECT DISTINCT 
        id
    FROM @t
)A
OUTER APPLY(
    SELECT 
        [values]= STUFF(REPLACE(REPLACE(
            (
                SELECT value FROM @t N
                WHERE id = A.id
                FOR XML AUTO
            ), ‘<N value="‘, ‘,‘), ‘"/>‘, ‘‘), 1, 1, ‘‘)
)N

/*--结果
id          values
----------- ----------------
1           aa,bb
2           aaa,bbb,ccc
(2 行受影响)
--*/

IT忍者神龟之一句sql语句——连接同一字段的所有值

标签：style   io   color   ar   os   sp   for   数据   on   

原文地址：http://blog.csdn.net/vipyhd/article/details/40891781