[英]Query complex XML in SQL Server 2008 R2
我試圖通過SQL Server 2008 R2中的XML進行解析,但是遇到了一些問題。 我正在嘗試解析每個父節點的項目,但似乎無法獲得准確的數據。 XML數據如下:
<Project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="Project.xsd" Name="Job">
<Design>
<Catalog>
<Identification>
<Name>Group1</Name>
</Identification>
<FeatureSet ID="IDFS-1" Type="Style">
<Description>Style1</Description>
</FeatureSet>
<Item ID="IDI-1-2730">
<UserCode>Item1</UserCode>
<LineItemNumber>1</LineItemNumber>
</Item>
<Item ID="IDI-1-1595">
<UserCode>Item2</UserCode>
<LineItemNumber>2</LineItemNumber>
</Item>
</Catalog>
<Catalog>
<Identification>
<Name>Group2</Name>
</Identification>
<FeatureSet ID="IDFS-1" Type="Style">
<Description>Style2</Description>
</FeatureSet>
<Item ID="IDI-1-2730">
<UserCode>Item3</UserCode>
<LineItemNumber>1</LineItemNumber>
</Item>
</Catalog>
</Design>
</Project>
到目前為止,這是我所使用的SQL,但似乎沒有用。
select
x.d.query('./UserCode').value('.','char(40)') as UserCode
,x.d.query('./LineItemNumber').value('.','char(40)') as lineitemnumber
,i.d.query('./Name').value('.','nvarchar(200)') as [Group]
,u.d.query('./Description').value('.','nvarchar(200)') as Style
from
@xml.nodes('/Project/Design/Catalog/Item') as x(d)
outer apply
@xml.nodes('/Project/Design/Catalog/Identification') as i(d)
outer apply
@xml.nodes('/Project/Design/Catalog/FeatureSet') as u(d)
顯然,我正在使用XML數據類型將@xml
設置為上述xml數據。
以下是我得到的結果:
UserCode lineitemnumber Group Style
Item1 1 Group1 Style1
Item1 1 Group1 Style2
Item1 1 Group2 Style1
Item1 1 Group2 Style2
Item2 2 Group1 Style1
Item2 2 Group1 Style2
Item2 2 Group2 Style1
Item2 2 Group2 Style2
Item3 1 Group1 Style1
Item3 1 Group1 Style2
Item3 1 Group2 Style1
Item3 1 Group2 Style2
我正在尋找的是:
UserCode lineitemnumber Group Style
Item1 1 Group1 Style1
Item2 2 Group1 Style1
Item3 1 Group2 Style2
每個目錄只有一個標識/描述,也只有一個功能集/描述
select
x.d.query('./UserCode').value('.','char(40)') as UserCode
,x.d.query('./LineItemNumber').value('.','char(40)') as lineitemnumber
,x.d.query('../Identification/Name').value('.','nvarchar(200)') as [Group]
,x.d.query('../FeatureSet/Description').value('.','nvarchar(200)') as Style
from @xml.nodes('/Project/Design/Catalog/Item') as x(d)
如@Backs所述,父節點查詢的性能可能很差,因此可以通過從父節點到子節點進行交叉應用來避免這種情況,然后可以根據需要引用其中任一部分:
select
-- these 2 are from the child (Item)
c.i.value('(UserCode/text())[1]', 'char(40)') as UserCode,
c.i.value('(LineItemNumber/text())[1]', 'char(40)') as lineitemnumber,
-- these are from the parent (Catalog)
d.c.value('(Identification/Name/text())[1]', 'nvarchar(200)') as [Group],
d.c.value('(FeatureSet/Description/text())[1]', 'nvarchar(200)') as Style
from
@xml.nodes('/Project/Design/Catalog') d(c) -- the parent node
cross apply d.c.nodes('Item') c(i) -- the Item nodes under the Catalog parent
與之相比,這有更好的估計計划
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