--1. 创建表，添加测试数据 CREATE TABLE tb(id int, [value] varchar(10)) INSERT tb SELECT 1, 'aa' UNION ALL SELECT 1, 'bb' UNION ALL SELECT 2, 'aaa' UNION ALL SELECT 2, 'bbb' UNION ALL SELECT 2, 'ccc'
--SELECT * FROM tb /**//* id value ----------- ---------- 1 aa 1 bb 2 aaa 2 bbb 2 ccc
(5 row(s) affected) */
--2 在SQL2000只能用自定义函数实现 ----2.1 创建合并函数fn_strSum，根据id合并value值 GO CREATE FUNCTION dbo.fn_strSum(@id int) RETURNS varchar(8000) AS BEGIN DECLARE @values varchar(8000) SET @values = '' SELECT @values = @values + ',' + value FROM tb WHERE id=@id RETURN STUFF(@values, 1, 1, '') END GO
-- 调用函数 SELECT id, VALUE = dbo.fn_strSum(id) FROM tb GROUP BY id DROP FUNCTION dbo.fn_strSum
----2.2 创建合并函数fn_strSum2，根据id合并value值 GO CREATE FUNCTION dbo.fn_strSum2(@id int) RETURNS varchar(8000) AS BEGIN DECLARE @values varchar(8000) SELECT @values = isnull(@values + ',', '') + value FROM tb WHERE id=@id RETURN @values END GO
-- 调用函数 SELECT id, VALUE = dbo.fn_strSum2(id) FROM tb GROUP BY id DROP FUNCTION dbo.fn_strSum2
--3 在SQL2005/SQL2008中的新解法 ----3.1 使用OUTER APPLY SELECT * FROM (SELECT DISTINCT id FROM tb) A OUTER APPLY( SELECT [values]= STUFF(REPLACE(REPLACE( ( SELECT value FROM tb N WHERE id = A.id FOR XML AUTO ), 'N value="', ','), '"/>', ''), 1, 1, '') )N
----3.2 使用XML SELECT id, [values]=STUFF((SELECT ','+[value] FROM tb t WHERE id=tb.id FOR XML PATH('')), 1, 1, '') FROM tb GROUP BY id
--4 删除测试表tb drop table tb
/**//* id values ----------- -------------------- 1 aa,bb 2 aaa,bbb,ccc
