nested xml extract

  • Hi all,

    I have a problem with a nested xml. It's triple nested, and the innermost part of it is null in some cases. I created a simplified version of that xml, as you can see below. I'd like to kniow how to modify my select statement so it shows all elements of that xml, and the null fields are to be null.

    What I get is this:

    RecIDfield1RecID2field2RecID3field3field4field5

    1212122TOS

    but I want three rows.

    Here's my xml and my select statement...

    DECLARE @xml XML

    SET @xml = '

    <OuterRoot>

    <Outer>

    <RecID>1</RecID>

    <field1>2</field1>

    <InnerRoot>

    <Inner>

    <RecID2>1</RecID2>

    <field2>2</field2>

    <InnermostRoot>

    <Innermost>

    <RecID3>1</RecID3>

    <field3>2</field3>

    <field4>2</field4>

    <field5>TOS</field5>

    </Innermost>

    </InnermostRoot>

    </Inner>

    </InnerRoot>

    </Outer>

    <Outer>

    <RecID>2</RecID>

    <field1>3</field1>

    <InnerRoot>

    <Inner>

    <RecID2>2</RecID2>

    <field2>3</field2>

    </Inner>

    </InnerRoot>

    </Outer>

    <Outer>

    <RecID>3</RecID>

    <field1>2</field1>

    <InnerRoot>

    <Inner>

    <RecID2>3</RecID2>

    <field2>2</field2>

    </Inner>

    </InnerRoot>

    </Outer>

    </OuterRoot>'

    SELECT

    Outers.Element.value('(RecID)[1]', 'INT')AS RecID,

    Outers.Element.value('(field1)[1]', 'INT')AS field1,

    Inners.Element.value('(RecID2)[1]', 'INT')AS RecID2,

    Inners.Element.value('(field2)[1]', 'INT')AS field2,

    Innermost.Element.value('(RecID3)[1]', 'INT')AS RecID3,

    Innermost.Element.value('(field3)[1]', 'INT')AS field3,

    Innermost.Element.value('(field4)[1]', 'INT')AS field4,

    Innermost.Element.value('(field5)[1]', 'VARCHAR(3)') AS field5

    FROM

    @xml.nodes('/OuterRoot/Outer') AS Outers(Element)

    CROSS APPLY

    Outers.Element.nodes('InnerRoot/Inner') AS Inners(Element)

    CROSS APPLY

    Inners.Element.nodes('InnermostRoot/Innermost') AS Innermost(Element)

    I appreciate some help.

  • Can you show me what your 3 rows should look like?

    _________________________________
    seth delconte
    http://sqlkeys.com

  • Sure. Here's simplified (please ignore lack of PK FK etc) set up to create the xml...

    DECLARE @tmp1 TABLE (

    RecID INT,

    field1 INT)

    DECLARE @tmp2 TABLE (

    RecID2 INT,

    field2 INT)

    DECLARE @tmp3 TABLE (

    RecID3 INT,

    field3 INT,

    field4 INT,

    field5 VARCHAR(3))

    INSERT INTO @tmp1

    VALUES (1, 2), (2, 3), (3, 2)

    INSERT INTO @tmp2

    VALUES (1, 2), (2, 3), (3, 2)

    INSERT INTO @tmp3

    VALUES (1, 2, 2, 'TOS'), (4, 5, 3, 'TWQ'), (6, 7, 3, 'KSD')

    SELECT

    W.RecID,

    W.field1, (

    SELECT

    U.RecID2,

    U.field2, (

    SELECT

    P.RecID3,

    P.field3,

    P.field4,

    P.field5

    FROM

    @tmp3 P

    WHERE

    P.RecID3 = U.RecID2

    FOR XML PATH ('Innermost'), ROOT('InnermostRoot'), TYPE )

    FROM

    @tmp2 U

    WHERE U.RecID2 = W.RecID

    FOR XML PATH ('Inner'), ROOT('InnerRoot'), TYPE )

    FROM

    @tmp1 W

    FOR XML PATH ('Outer'), ROOT('OuterRoot'), TYPE

    The result is a product of left join of all three tables (without xml, just select) ... Maybe I'm forming the xml wrong?

    RecIDfield1RecID2field2RecID3field3field4field5

    1212122TOS

    2323NULLNULLNULLNULL

    3232NULLNULLNULLNULL

  • If you are not opposed to hard-coding in empty nodes in an ISNULL, this works:

    SELECT

    W.RecID,

    W.field1, (

    SELECT

    U.RecID2,

    U.field2,

    isnull((

    SELECT

    P.RecID3,

    P.field3,

    P.field4,

    P.field5

    FROM

    @tmp3 P

    WHERE

    P.RecID3 = U.RecID2

    FOR XML PATH ('Innermost'), ROOT('InnermostRoot'),TYPE ),

    '<InnermostRoot><Innermost>

    <RecID3> </RecID3>

    <field3> </field3>

    <field4> </field4>

    <field5> </field5>

    </Innermost></InnermostRoot>')

    FROM

    @tmp2 U

    WHERE U.RecID2 = W.RecID

    FOR XML PATH ('Inner'), ROOT('InnerRoot'),TYPE )

    FROM

    @tmp1 W

    FOR XML PATH ('Outer'), ROOT('OuterRoot'), TYPE

    It outputs:

    RecID field1 RecID2 field2 RecID3 field3 field4 field5

    ----------- ----------- ----------- ----------- ----------- ----------- ----------- ------

    1 2 1 2 1 2 2 TOS

    2 3 2 3 0 0 0

    3 2 3 2 0 0 0

    (3 row(s) affected)

    _________________________________
    seth delconte
    http://sqlkeys.com

  • Well, probably not a problem if this is last resort. Or I assume I might change some table structure to deal with this.

    Thank you so much, greatly appreciated 🙂

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