SQL 服务器枢轴 Table，空结果

Question

这是我知道的一个热门问题。我只是在学习数据透视表，不知道我哪里出错了。

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 help/guidance 非常感谢。我知道这应该很容易，但我似乎无法全神贯注。

结果：

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

想要：

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

您需要创建另一个包含 Code1, Code2, Code3 值的列：

;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;

更新

如果您有未知数量的代码，则需要动态 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;

SQL 服务器枢轴 Table，空结果

SQL Server Pivot Table, Null Results

sql

tsql

sql-server

pivot