XML Column - three levels hierarchy - with Cross Apply

问题

My prior question was solved here. Now I'm adding one more level of complexity to it - data that is nested parent, child, grandchild.

You can see and run sample here: https://dbfiddle.uk/?rdbms=sqlserver_2019&fiddle=df2766c95383d4c8c2d1f55539634341

Sample Code, where Leg1 might be the trip out, and Leg2 might be the trip back. Each leg can have one or more flights.

DECLARE @xml XML='
<Reservation>
  <Name>Neal</Name>
    <Leg seq=''1''>
      <Flight>12</Flight>
    </Leg>
    <Leg seq=''2''>
      <Flight>34</Flight>
      <Flight>56</Flight>
    </Leg>
</Reservation>'
select @xml

DECLARE @xmlTable TABLE (
    xmlDoc Xml
);
Insert into @xmltable values (@xml)
--Select xmlDoc from @XmlTable 

Select xmlDoc.value('(//Name)[1]', 'varchar(30)') as Passenger,
       XmlData2.xmlDoc2.query('.') as XmlData2,
       XmlData2.xmlDoc2.value('./@seq', 'int') as LegSeq,
       XmlData3.xmlDoc3.query('.') as XmlData3,
       XmlData3.xmlDoc3.value('.', 'varchar(20)') as Flight
FROM @xmlTable as t
     CROSS APPLY 
        t.xmlDoc.nodes('//Leg') AS XmlData2(xmlDoc2)
     CROSS APPLY 
        t.xmlDoc.nodes('//Flight') AS XmlData3(xmlDoc3)

The issue is that I'm still need 3 rows returned, but now I'm getting 6.

Expected result would be:

Neal LegSeq=1 Flight=12 
Neal LegSeq=2 Flight=34
Neal LegSeq=2 Flight=56

Microsoft SQL Server 2019 (RTM) - 15.0.2000.5 (X64) Sep 24 2019 13:48:23 Copyright (C) 2019 Microsoft Corporation Developer Edition (64-bit) on Windows Server 2019 Standard 10.0 (Build 17763: )

回答1:

In the second apply, you want to be applying to the nodes from XmlData2.xmlDoc2. The way you have it written, it looks for nodes from the root again, which will apply to all Flight elements in the XML.

DECLARE @xml XML='
<Reservation>
  <Name>Neal</Name>
    <Leg seq=''1''>
      <Flight>12</Flight>
    </Leg>
    <Leg seq=''2''>
      <Flight>34</Flight>
      <Flight>56</Flight>
    </Leg>
</Reservation>'
select @xml

DECLARE @xmlTable TABLE (
    xmlDoc Xml
);
Insert into @xmltable values (@xml)
--Select xmlDoc from @XmlTable 

Select xmlDoc.value('(//Name)[1]', 'varchar(30)') as Passenger,
       XmlData2.xmlDoc2.query('.') as XmlData2,
       XmlData2.xmlDoc2.value('./@seq', 'int') as LegSeq,
       XmlData3.xmlDoc3.query('.') as XmlData3,
       XmlData3.xmlDoc3.value('.', 'varchar(20)') as Flight
FROM @xmlTable as t
     CROSS APPLY 
        t.xmlDoc.nodes('//Leg') AS XmlData2(xmlDoc2)
     CROSS APPLY 
        XmlData2.xmlDoc2.nodes('Flight') AS XmlData3(xmlDoc3);

来源：https://stackoverflow.com/questions/62008546/xml-column-three-levels-hierarchy-with-cross-apply