--> 生成测试数据: @tb
CREATE TABLE tb (商品id INT,商品名称 VARCHAR(4),客户名称 VARCHAR(4),日期 DATETIME,销量 INT)
INSERT INTO tb
SELECT 1,'a','张三','2009-1-1',1 UNION ALL
SELECT 1,'a','李四','2009-1-5',2 UNION ALL
SELECT 2,'b','王二','2009-1-5',3 UNION ALL
SELECT 2,'b','李四','2009-1-5',5 UNION ALL
SELECT 3,'c','王二','2009-1-1',6 UNION ALL
SELECT 1,'a','张三','2009-2-1',8 UNION ALL
SELECT 1,'a','张三','2009-2-2',2

--SQL查询如下:

DECLARE @sql varchar(8000);
SET @sql = '';

SELECT ID = IDENTITY(int,1,1),CONVERT(varchar(6),日期,112) AS 日期 INTO #tmp1
FROM tb GROUP BY CONVERT(varchar(6),日期,112);

SELECT DISTINCT 商品名称 INTO #tmp2 FROM tb;

DECLARE @id int,@日期 varchar(6);
SET @id = (SELECT TOP 1 id FROM #tmp1 ORDER BY id);
WHILE @id IS NOT NULL
    BEGIN
         SET @日期 = (SELECT 日期 FROM #tmp1 WHERE ID = @id);
         
         SELECT @sql = @sql + ',SUM(CASE WHEN 商品名称 = ''' + 商品名称 
                            + ''' AND CONVERT(varchar(6),日期,112) = ''' + @日期 
                            + ''' THEN 销量 ELSE 0 END) AS [' + @日期 + '_' 
                            + 商品名称 + '销量]'
         FROM #tmp2
         SET @sql = @sql + ',SUM(CASE WHEN CONVERT(varchar(6),日期,112)=''' 
                         + @日期 + ''' THEN 销量 ELSE 0 END) AS [' + @日期 + '_累计销量]'
         SET @id = (SELECT TOP 1 id FROM #tmp1 WHERE id > @id ORDER BY id);
    END

SELECT @sql = @sql + ',SUM(CASE WHEN 商品名称 = ''' + 商品名称 
                   + ''' THEN 销量 ELSE 0 END) AS [' + 商品名称 + '销量]'
FROM #tmp2;

EXEC('SELECT ISNULL(客户名称,''累计'') AS 客户名称'+@sql+',SUM(销量) AS 累计 FROM tb
         GROUP BY 客户名称 WITH ROLLUP')



DROP TABLE #tmp1,#tmp2;
DROP TABLE tb;

------解决方案--------------------

SQL code
--> 生成测试数据: @tb  --drop table tb 
 create table Tb (商品id INT,商品名称 VARCHAR(4),客户名称 VARCHAR(4),日期 DATETIME,销量 INT) 
 INSERT INTO tb 
 SELECT 1,'a','张三','2009-1-1',1 UNION ALL 
 SELECT 1,'a','李四','2009-1-5',2 UNION ALL 
 SELECT 2,'b','王二','2009-1-5',3 UNION ALL 
 SELECT 2,'b','李四','2009-1-5',5 UNION ALL 
 SELECT 3,'c','王二','2009-1-1',6 UNION ALL 
 SELECT 1,'a','张三','2009-2-1',8 UNION ALL 
 SELECT 1,'a','张三','2009-2-2',2 
  
 select distinct a.商品id,a.商品名称,b.日期 into #a from tb a 
 cross join(select distinct CONVERT(varchar(6),日期,112) as 日期 from tb)b 
  
  
 declare @sql nvarchar(4000) 
 SET @sql=N'select isnull([客户名称],N''总计'') as 客户名称'   --初始化变量必须 
 select @sql=@sql+N','+ 
         QUOTENAME(日期+N'_'+a.商品名称+N'销量')+ 
           N'=sum( 
               case when [商品名称]='+quotename(a.商品名称,N'''')+