我一直试图使用FOR XML而没有成功执行以下操作。
来源表:
Country | ID | 1950 | 1955
-----------------------------------------------------
Country 1 | 1 | 2.43 | 2.55
Country 2 | 2 | 4.54 | 42.15
期望的输出:
<locations>
<location>
<loc name='Country 1' id='1' />
<dub>
<data year='1950' value='2.43' />
<data year='1955' value='2.55' />
</dub>
</location>
<location>
<loc name='Country 2' id='2' />
<dub>
<data year='1950' value='4.54' />
<data year='1955' value='42.15' />
</dub>
</location>
</locations>
是否有必要对dub元素进行解包?我希望最简单的SQL查询成为可能。
我认为FOR XML太难用了。您应该能够仅使用列名称上的简单XPath指定层次结构,但它不会接受,例如,[dub/data/@year=1955/@value]
作为列[1950]
的名称。
答案 0 :(得分:2)
MS SQL Server 2012架构设置:
create table YourTable
(
Country varchar(20),
ID int,
[1950] numeric(5,2),
[1955] numeric(5,2)
)
insert into YourTable values
('Country 1', 1, 2.43, 2.55),
('Country 2', 2, 4.54, 42.15)
查询1 :
select T.Country as 'loc/@name',
T.ID as 'loc/@id',
(
select 1950 as 'data/@year',
T.[1950] as 'data/@value',
null,
1955 as 'data/@year',
T.[1955] as 'data/@value'
for xml path(''), type
) as dub
from YourTable as T
for xml path('location'), root('locations'), type
<强> Results 强>:
<locations>
<location>
<loc name="Country 1" id="1" />
<dub>
<data year="1950" value="2.43" />
<data year="1955" value="2.55" />
</dub>
</location>
<location>
<loc name="Country 2" id="2" />
<dub>
<data year="1950" value="4.54" />
<data year="1955" value="42.15" />
</dub>
</location>
</locations>