sqlserver 分组合并

 --创建 test 表 ，插入数据
    CREATE TABLE test(code varchar(50),[values] varchar(10),[count] int)
    INSERT test SELECT '001','aa',1
    UNION ALL SELECT '001','bb',2
    UNION ALL SELECT '002','aaa',4
    UNION ALL SELECT '002','bbb',5
    UNION ALL SELECT '002','ccc',3;
    --方法一
    --将多行合并成一行，并做分组统计
    SELECT code,[values] =
    stuff(b.[values].value('/R[1]','nvarchar(max)'),''),[count]
    FROM (SELECT code,sum([count]) as [count]
    FROM test
    GROUP BY code) a
    CROSS apply (
    SELECT [values] =(
    SELECT N',' + [values] FROM test
    WHERE code = a.code
    FOR XML PATH(''),ROOT('R'),TYPE
    )
    ) b;
    --方法二
    ---sql2005中的新解法  使用XML
    SELECT code,data=STUFF((SELECT ','+[values] FROM test t WHERE code=t1.code FOR XML PATH('')),1,sum([count]) as [count]
    FROM test t1
    GROUP BY code
    --查询结果
    --001   aa,bb   3
    --002   aaa,bbb,ccc   12
    drop table test