动态反透视和拆分列 SQL Server 2012
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【中文标题】动态反透视和拆分列 SQL Server 2012【英文标题】：Dynamic Unpivot and split Columns SQL Server 2012 【发布时间】：2015-10-20 12:31:03 【问题描述】：我有一个具有 20 列的 MarketOutput 表
[Region] [LOB] [GWP 2013] [GWP 2014] [LR 2013] [LR 2014]
-------------------------------------------------------------
North Workers 38902.50 37,972,404 89 82
我想动态地将列更改为行。 Region和LOB是固定列，[GWP 2013]、[GWP 2014]、[LR 2013]、[LR 2014]是动态列。
明年他们将是[GWP 2015]，[LR 2015]
我想取消透视该列并将 [GWP 2014] 拆分为两列 [GWP], [2014]。
输出应该是这样的
Region [LOB] [Metrics] [Year] [Value]
--------------------------------------------------
North Workers GWP 2013 38902.50
North Workers GWP 2014 37,972,404
North Workers LR 2013 89
North Workers LR 2014 82
您能否建议如何做到这一点？
我是 SQL Server 中枢轴的新手
我还想每次使用动态列表将输出插入到一个新表中
【问题讨论】：
unpivot with dynamic columns plus column names的可能重复 你真的应该考虑修复你的数据库。至少年份应该是行中的一个值，也可能是 LR / GWP。 【参考方案1】：您只需要在执行UNPIVOT 之后拆分列，如下所示：
WITH Unpivoted
AS
(
SELECT region, lob, columns, value
FROM Regions
UNPIVOT
(
columns
FOR value IN([GWP 2013] , [GWP 2014] ,
[LR 2013] , [LR 2014] ,
[GWP 2015], [LR 2015])
) AS u
)
SELECT
region,
lob,
columns,
CAST(CASE WHEN value LIKE 'GWP%' THEN REPLACE(value,'GWP ', '')
WHEN value LIKE 'LR%' THEN REPLACE(value,'LR ', '')
END AS INT) AS Year,
CASE WHEN value LIKE 'GWP%' THEN 'GWP'
WHEN value LIKE 'LR%' THEN 'LR'
END AS Metrics
FROM Unpivoted;
当然你应该动态地做它以避免手动列出列并动态地做它：
DECLARE @cols AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);
select @cols = STUFF((SELECT distinct ',' +
QUOTENAME(column_name)
FROM information_schema.columns
WHERE table_name = 'Regions'
AND COLUMN_NAME <> 'Region'
AND COLUMN_NAME <> 'LOB'
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
, 1, 1, '');
SELECT @query = 'WITH Unpivoted
AS
(
SELECT region, lob, columns, value
FROM Regions
UNPIVOT
(
columns
FOR value IN('+ @cols + ')
) AS u
)
SELECT
region,
lob,
columns,
CAST(CASE WHEN value LIKE ''GWP%'' THEN REPLACE(value,''GWP '', '''')
WHEN value LIKE ''LR%'' THEN REPLACE(value,''LR '', '''')
END AS INT) AS Year,
CASE WHEN value LIKE ''GWP%'' THEN ''GWP''
WHEN value LIKE ''LR%'' THEN ''LR''
END AS Metrics
FROM Unpivoted';
EXECUTE(@query);
这应该可以正常工作，假设：
[GWP 2013] , [GWP 2014] , [LR 2013] , [LR 2014] , [GWP 2015], [LR 2015], ... etc 的所有列都采用相同的格式（GWP 或 LR，然后是空格，然后是年份，以及
所有的列都是相同的数据类型int或十进制，如果数据类型不一样你应该在执行unpivot之前将它们全部转换为一种数据类型，否则你会得到一个错误。
SQL Fiddle Demo
这会给你：
| region | lob | columns | Year | Metrics |
|--------|---------|----------|------|---------|
| North | Workers | 38902.5 | 2013 | GWP |
| North | Workers | 37972404 | 2014 | GWP |
| North | Workers | 70 | 2015 | GWP |
| North | Workers | 89 | 2013 | LR |
| North | Workers | 82 | 2014 | LR |
| North | Workers | 80 | 2015 | LR |
更新：
我使用FOR XML PATH('') .. 将所有值列表连接到一个字符串中，这是 SQL Server 中的一种解决方法。 @cols 的值将是字符串：[GWP 2013], [GWP 2014], ...。
如果您的字段数据类型不同，您必须在执行UNPVOT 之前对所有将在锚查询中取消透视的列进行强制转换，如下所示：
SELECT @query = 'WITH Unpivoted
AS
(
SELECT region, lob, columns, value
FROM
(
SELECT
region,
lob,
CAST([GWP 2013] AS DECIMAL(10,2)) AS [GWP 2013],
CAST([GWP 2014] AS DECIMAL(10,2)) AS [GWP 2014],
... etc
FROM Regions
) AS t
UNPIVOT
(
columns
FOR value IN('+ @cols + ')
) AS u
)
SELECT
region,
lob,
columns,
CAST(CASE WHEN value LIKE ''GWP%'' THEN REPLACE(value,''GWP '', '''')
WHEN value LIKE ''LR%'' THEN REPLACE(value,''LR '', '''')
END AS INT) AS Year,
CASE WHEN value LIKE ''GWP%'' THEN ''GWP''
WHEN value LIKE ''LR%'' THEN ''LR''
END AS Metrics
FROM Unpivoted';
如果您发现手动为所有列编写强制转换很困难，您可以动态生成并附加它，例如：
DECLARE @colsCasted AS NVARCHAR(MAX);
select @colsCasted = STUFF((SELECT distinct ',' +
'CAST(' + QUOTENAME(column_name) + 'AS DECIMAL(10,2)) AS ' + QUOTENAME(column_name)
FROM information_schema.columns
WHERE table_name = 'Regions'
AND COLUMN_NAME <> 'Region'
AND COLUMN_NAME <> 'LOB'
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
, 1, 1, '');
然后在动态查询中将该值附加到它：
SELECT @query = 'WITH Unpivoted
AS
(
SELECT region, lob, columns, value
FROM
(
SELECT region, lob,
' + @colsCasted + '
FROM Regions
) AS t
UNPIVOT
(
columns
FOR value IN('+ @cols + ')
) AS u
)
SELECT
region,
lob,
columns,
CAST(CASE WHEN value LIKE ''GWP%'' THEN REPLACE(value,''GWP '', '''')
WHEN value LIKE ''LR%'' THEN REPLACE(value,''LR '', '''')
END AS INT) AS Year,
CASE WHEN value LIKE ''GWP%'' THEN ''GWP''
WHEN value LIKE ''LR%'' THEN ''LR''
END AS Metrics
FROM Unpivoted';
EXECUTE(@query);
【讨论】：
这很有魅力。你能解释一下 xml_path 是如何工作的吗？ 您还提到我需要转换，因为我的所有字段都不是 int 或 decimal，有些是 nvarchar。这种转换需要在单独的动态查询中完成吗？还是会成为@Query 的一部分？ 这是什么意思 FOR XML PATH(''), TYPE ).value('.', 'NVARCHAR(MAX)') , 1, 1, ''); @Mohit - 我更新了我的答案以澄清所有这些疑问，请在答案中查看我的更新。 感谢 Mahmoud 的澄清。非常感谢您的努力以上是关于动态反透视和拆分列 SQL Server 2012的主要内容，如果未能解决你的问题，请参考以下文章