sql - 将 XML 格式化为 select 语句

Question

DECLARE @Data AS XML = '
<Catalog>
<Artist>
    <name>Wolfgang</name>
    <name>Razorback</name>
</Artist>
<Album>
    <Category>Rock</Category>
    <Category>Alternative</Category>
</Album>
</Catalog>'

SELECT 
   B.value('(text())[1]','varchar(15)') as Artist,
   C.value('(text())[1]','varchar(15)') as Album
FROM  @Data.nodes('/Catalog') AS Catalog(A)
  CROSS APPLY A.nodes('Artist/name') as Artist(B)
  CROSS APPLY A.nodes('Album/Category') as Album(C)

我期待的结果应该是这样的，我真的只是想把艺术家作为第一列，专辑作为第二列

但它返回了这个查询，

Answer 1

你的xml不是很好。你可以这样做：

;with cte_artist as (
    select
        row_number() over(order by (select '1')) as rn,
        T.C.value('text()[1]','varchar(15)') as Artist
    from @Data.nodes('/Catalog/Artist/name') as T(C)
), cte_album as (
    select
        row_number() over(order by (select '1')) as rn,
        T.C.value('text()[1]','varchar(15)') as Album
    from @Data.nodes('/Catalog/Album/Category') as T(C)
)
select
    a1.Artist,
    a2.Album
from cte_artist as a1
    full outer join cte_album as a2 on a2.rn = a1.rn

sql fiddle demo

但更好的方法是创建这样的 xml（或您想要的任何其他嵌套方式）：

<Catalog>
    <Album name="Rock album">
        <Category>Rock</Category>
        <Artist name="Wolfgang"/>
    </Album>
    <Album name="Alternative album">
        <Category>Alternative</Category>
        <Artist name="Razorback"/>
    </Album>
</Catalog>

所以你可以这样查询：

select
    T.C.value('@name','varchar(15)') as name,
    T.C.value('(Category/text())[1]','varchar(15)') as Category,
    T.C.value('Artist[1]/@name','varchar(15)') as Artist
from @Data.nodes('/Catalog/Album') as T(C)