SQL Server数据透视表，空值结果

Question

这是我知道的一个受欢迎的问题。我只是了解数据透视表，不知道我哪里出错。

create table #test 
(
    id varchar(4), 
    code varchar(2), 
    received_dt varchar(8) 
) 

insert into #test values ('1234','10','20150312') 
insert into #test values ('1234','71','20150312') 
insert into #test values ('1234','C5','20150312') 
insert into #test values ('4321','10','20150312') 
insert into #test values ('4321','71','20150312') 
insert into #test values ('987','10','20150312') 
insert into #test values ('987','71','20150312') 
insert into #test values ('987','C5','20150312') 

select id, [code1], [code2], [code3] 
from #test 
pivot(MAX(code) for code in ([code1], [code2], [code3])) as pvt 

drop table #test 

任何帮助/指导，非常感谢。我知道这应该很容易，但我似乎无法围绕它围绕我的大脑。

结果：

ID  Code1 Code2 Code3 
1234 NULL NULL NULL 
4321 NULL NULL NULL 
987  NULL NULL NULL 

旺旺：

ID  Code1 Code2 Code3 
1234 10  71  C5 
4321 10  71  NULL 
987  10  71  C5 

编辑有很多代码值。

Answer 1

你需要创建一个包含Code1, Code2, Code3值的另一列：

;WITH CTE AS 
(
    SELECT *, 
      RN = 'Code' + 
       CAST(ROW_NUMBER() OVER(PARTITION BY ID ORDER BY code) AS CHAR(1)) 
    FROM #test 
) 
SELECT id, [code1], [code2], [code3] 
FROM CTE 
PIVOT(MAX(code) for RN in ([code1], [code2], [code3])) as pvt; 

UPDATE

如果你有数目不详的代码，你需要动态SQL：

DECLARE @sql NVARCHAR(MAX) = N'', @cols NVARCHAR(MAX) = N''; 

WITH CTE AS 
(
    SELECT *, 
      RN = 'Code' + 
       CAST(ROW_NUMBER() OVER(PARTITION BY ID ORDER BY code) AS CHAR(1)) 
    FROM #test 
) 
SELECT @cols += STUFF((SELECT ',' + QUOTENAME(RN) 
         FROM CTE 
         GROUP BY RN 
         FOR XML PATH('')), 1, 1, ''); 


SET @sql = N' 
SELECT * 
FROM ( SELECT *, 
       RN = ''Code'' + 
       CAST(ROW_NUMBER() OVER(PARTITION BY ID ORDER BY code) AS CHAR(1)) 
    FROM #test) AS d 
PIVOT(MAX(code) for RN in (' + @cols + ')) AS p;'; 

EXEC sp_executesql @sql;