sql - XML 粉碎动态 SQL
问题描述
使用此处第一个答案的说明,我试图在 SQL Server 2012 表中分解一些 XML,如下所示:
表A
+------+--------+
| ID | ColXML |
+------+--------+
| 0001 | <xml1> |
| 0002 | <xml2> |
| ... | ... |
+------+--------+
xml1 看起来像这样:
<Attributes>
<Attribute name="address1">301 Main St</Attribute>
<Attribute name="city">Austin</Attribute>
</Attributes>
xml2 看起来像这样:
<Attributes>
<Attribute name="address1">501 State St</Attribute>
<Attribute name="address2">Suite 301</Attribute>
<Attribute name="state">Texas</Attribute>
</Attributes>
在任何给定的行中都有不同数量的属性。
我正在尝试将其展平为如下所示的关系表:
+------+--------------+-----------+--------+-------+
| ID | address1 | address2 | city | state |
+------+--------------+-----------+--------+-------+
| 0001 | 301 Main St | NULL | Austin | NULL |
| 0002 | 501 State St | Suite 301 | NULL | Texas |
+------+--------------+-----------+--------+-------+
这是我尝试过的代码,它在表#T 中返回 0 行:
select dense_rank() over(order by ID, I.N) as ID,
F.N.value('(*:Name/text())[1]', 'varchar(max)') as Name,
F.N.value('(*:Values/text())[1]', 'varchar(max)') as Value
into #T
from TableA as T
cross apply T.Attributes.nodes('/ColXML') as I(N)
cross apply I.N.nodes('ColXML') as F(N);
declare @SQL nvarchar(max)
declare @Col nvarchar(max);
select @Col =
(
select distinct ','+quotename(Name)
from #T
for xml path(''), type
).value('substring(text()[1], 2)', 'nvarchar(max)');
set @SQL = 'select '+@Col+'
from #T
pivot (max(Value) for Name in ('+@Col+')) as P';
exec (@SQL);
任何帮助将不胜感激。
解决方案
这是用于分解表中的 XML的 DDL 和XQuery 。不需要任何动态 SQL。MS SQL Server 支持XQuery 1.0 标准的一个子集。Microsoft 需要实施 XQuery 3.1 以使其数据库更加强大。
SQL
-- DDL and sample data population, start
DECLARE @tbl TABLE (ID VARCHAR(10) PRIMARY KEY, ColXML XML);
INSERT INTO @tbl (ID, ColXML)
VALUES
('0001', N'<Attributes>
<Attribute name="address1">301 Main St</Attribute>
<Attribute name="city">Austin</Attribute>
</Attributes>'),
('0002', N'<Attributes>
<Attribute name="address1">501 State St</Attribute>
<Attribute name="address2">Suite 301</Attribute>
<Attribute name="state">Texas</Attribute>
</Attributes>');
-- DDL and sample data population, end
SELECT ID
, col.value('(Attribute[@name="address1"]/text())[1]','VARCHAR(30)') AS [address1]
, col.value('(Attribute[@name="address2"]/text())[1]','VARCHAR(30)') AS [address2]
, col.value('(Attribute[@name="city"]/text())[1]','VARCHAR(30)') AS [city]
, col.value('(Attribute[@name="state"]/text())[1]','VARCHAR(30)') AS [state]
FROM @tbl AS tbl
CROSS APPLY tbl.ColXML.nodes('/Attributes') AS tab(col);
输出
+------+--------------+-----------+--------+-------+
| ID | address1 | address2 | city | state |
+------+--------------+-----------+--------+-------+
| 0001 | 301 Main St | NULL | Austin | NULL |
| 0002 | 501 State St | Suite 301 | NULL | Texas |
+------+--------------+-----------+--------+-------+