sql多行合并查询
有如下结构access表
日期 单号 内容
6/25 1001 aaaaa
6/25 1001 BBBBB
6/25 1001 ccccc
6/25 1002 Aaaaaa
6/25 1002 bbbbbb
6/25 1003 Aaaaaa
求查询语法,显示内容为:
日期 单号 内容
6/25 1001 aaaaa,bbbbb,ccccc
6/25 1002 Aaaaaa,bbbbb
6/25 1003 Aaaaaa
[解决办法]
发表于：2008-10-29 10:59:201楼 得分:0 SQL code问题描述：无论是在sql 2000，还是在 sql 2005 中,都没有提供字符串的聚合函数， 所以，当我们在处理下列要求时，会比较麻烦：有表tb, 如下：id value----- ------1 aa1 bb2 aaa2 bbb2 ccc需要得到结果：id values------ -----------1 aa,bb2 aaa,bbb,ccc即， group by id, 求 value 的和（字符串相加）1. 旧的解决方法-- 1. 创建处理函数CREATE FUNCTION dbo.f_str(@id int)RETURNS varchar(8000)ASBEGIN DECLARE @r varchar(8000) SET @r = '' SELECT @r = @r + ',' + value FROM tb WHERE id=@id RETURN STUFF(@r, 1, 1, '')ENDGO-- 调用函数SELECt id, values=dbo.f_str(id) FROM tb GROUP BY id-- 2. 新的解决方法 -- 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)AOUTER 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,bb2 aaa,bbb,ccc(2 行受影响)--*/CSDN 社区帖子地址 附: 合并与分拆的CLR， sql2005的示例中有：在安装sql 2005的示例后，默认安装目录为drive:\Program Files\Microsoft SQL Server\90\Samples\Engine\Programmability\CLR\StringUtilities中
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/*标题：按某字段合并字符串之一(简单合并)作者：爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开)时间：2008-11-06地点：广东深圳描述：将如下形式的数据按id字段合并value字段。id value----- ------1 aa1 bb2 aaa2 bbb2 ccc需要得到结果：id value------ -----------1 aa,bb2 aaa,bbb,ccc即：group by id, 求 value 的和（字符串相加）*/--1、sql2000中只能用自定义的函数解决create table tb(id int, value varchar(10))insert into tb values(1, 'aa')insert into tb values(1, 'bb')insert into tb values(2, 'aaa')insert into tb values(2, 'bbb')insert into tb values(2, 'ccc')gocreate function dbo.f_str(@id int) returns varchar(100)asbegin declare @str varchar(1000) set @str = '' select @str = @str + ',' + cast(value as varchar) from tb where id = @id set @str = right(@str , len(@str) - 1) return @strendgo--调用函数select id , value = dbo.f_str(id) from tb group by iddrop function dbo.f_strdrop table tb--2、sql2005中的方法create table tb(id int, value varchar(10))insert into tb values(1, 'aa')insert into tb values(1, 'bb')insert into tb values(2, 'aaa')insert into tb values(2, 'bbb')insert into tb values(2, 'ccc')goselect id, [value] = stuff((select ',' + [value] from tb t where id = tb.id for xml path('')) , 1 , 1 , '')from tbgroup by iddrop table tb--3、使用游标合并数据create table tb(id int, value varchar(10))insert into tb values(1, 'aa')insert into tb values(1, 'bb')insert into tb values(2, 'aaa')insert into tb values(2, 'bbb')insert into tb values(2, 'ccc')godeclare @t table(id int,value varchar(100))--定义结果集表变量--定义游标并进行合并处理declare my_cursor cursor local forselect id , value from tbdeclare @id_old int , @id int , @value varchar(10) , @s varchar(100)open my_cursorfetch my_cursor into @id , @valueselect @id_old = @id , @s=''while @@FETCH_STATUS = 0begin if @id = @id_old select @s = @s + ',' + cast(@value as varchar) else begin insert @t values(@id_old , stuff(@s,1,1,'')) select @s = ',' + cast(@value as varchar) , @id_old = @id end fetch my_cursor into @id , @valueENDinsert @t values(@id_old , stuff(@s,1,1,''))close my_cursordeallocate my_cursorselect * from @tdrop table tb
[解决办法]
-- =============================================================================-- Title: 在SQL中分类合并数据行-- Author: dobear Mail(MSN): dobear_0922@hotmail.com-- Environment: Vista + SQL2005-- Date: 2008-04-22-- =============================================================================--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 aa1 bb2 aaa2 bbb2 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GOCREATE FUNCTION dbo.fn_strSum(@id int)RETURNS varchar(8000)ASBEGIN DECLARE @values varchar(8000) SET @values = '' SELECT @values = @values + ',' + value FROM tb WHERE id=@id RETURN STUFF(@values, 1, 1, '')ENDGO-- 调用函数SELECT id, VALUE = dbo.fn_strSum(id) FROM tb GROUP BY idDROP FUNCTION dbo.fn_strSum----2.2 创建合并函数fn_strSum2，根据id合并value值GOCREATE FUNCTION dbo.fn_strSum2(@id int)RETURNS varchar(8000)ASBEGIN DECLARE @values varchar(8000) SELECT @values = isnull(@values + ',', '') + value FROM tb WHERE id=@id RETURN @valuesENDGO-- 调用函数SELECT id, VALUE = dbo.fn_strSum2(id) FROM tb GROUP BY idDROP FUNCTION dbo.fn_strSum2--3 在SQL2005中的新解法----3.1 使用OUTER APPLYSELECT * 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XMLSELECT id, [values]=STUFF((SELECT ','+[value] FROM tb t WHERE id=tb.id FOR XML PATH('')), 1, 1, '')FROM tbGROUP BY id--4 删除测试表tbdrop table tb/**//*id values----------- --------------------1 aa,bb2 aaa,bbb,ccc(2 row(s) affected)*/
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'Access 模块建立如下自定义函数
Function Same(id As Integer) As String Dim rs As Recordset Dim st As String st = "" Set rs = CurrentDb.OpenRecordset("Select * From Table_A where id=" + Str(id)) Do Until rs.EOF st = st + rs.Fields("name").Value + "," rs.MoveNext Loop Same = stEnd Function
[解决办法]
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