Sql Server：多行合并成一行，并做分组统计的两个方法

--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, 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