SQL Server：按元素名称计数的XML元素

Question

I have successfully obtained a count of sub elements using this query.

SELECT  
    raa.ApplicationXML.value('count(Root/ThirdParty/*)', 'Int') as [Bureau Count]
FROM 
    Table1 raa

However, I want to group this count by the actual name of the sub element.

My XML looks something like this:

Record 1:

<Root>
    <ThirdParty>
        <BureauRed />
        <BureauGreen />
        <BureauBlue />
    </ThirdParty>
</Root>

Record 2:

<Root>
    <ThirdParty>
        <BureauRed />
        <BureauPurple />
        <BureauBlue />
    </ThirdParty>
</Root>

Record 3:

<Root>
    <ThirdParty>
        <BureauGreen />
        <BureauRed />
        <BureauPurple />
        <BureauOrange />
        <BureauBlue />
    </ThirdParty>
</Root>

Not only do I need to pull the count of each bureau, but I need to get the name of the bureau (BureauRed, BureauGreen, BureauBlue, etc.) When I try to group by count I get the error:

XML methods are not allowed in a GROUP BY clause.

Using this query:

SELECT  
    raa.ApplicationXML.value('count(Root/ThirdParty/*)', 'Int') as [Bureau Count]
FROM 
    Table1 raa
GROUP BY
    raa.ApplicationXML.value('count(Root/ThirdParty/*)', 'Int')

How do I get the count and the name of the bureau?

I'm looking for this result:

Bureau         Count
============   =====
BureauRed      3
BureauGreen    2
BureauBlue     3
BureauPurple   2
BureauOrange   1

Answer 1

You need to extract the elements that are children of Root/ThirdParty first and use that derived table to do the counting.

DECLARE @tv TABLE(x XML);

INSERT INTO @tv(x)VALUES(
N'<Root>
    <ThirdParty>
        <BureauRed />
        <BureauGreen />
        <BureauBlue />
    </ThirdParty>
</Root>'),(
N'<Root>
    <ThirdParty>
        <BureauRed />
        <BureauPurple />
        <BureauBlue />
    </ThirdParty>
</Root>'),(
N'<Root>
    <ThirdParty>
        <BureauGreen />
        <BureauRed />
        <BureauPurple />
        <BureauOrange />
        <BureauBlue />
    </ThirdParty>
</Root>');

WITH bureaus AS (
    SELECT 
        bureau=n.v.value('local-name(.)','NVARCHAR(256)')
    FROM
        @tv
        CROSS APPLY x.nodes('/Root/ThirdParty/*') AS n(v)
)
SELECT
    bureau,
    [count]=COUNT(*)
FROM
    bureaus
GROUP BY
    bureau
ORDER BY
    bureau;

Answer 2

You can group after recieving data via XQuery:

DECLARE @xml1 xml = 
'<Root>
    <ThirdParty>
        <BureauRed />
        <BureauGreen />
        <BureauBlue />
    </ThirdParty>
</Root>';
DECLARE @xml2 xml = 
'<Root>
    <ThirdParty>
        <BureauRed />
        <BureauPurple />
        <BureauBlue />
    </ThirdParty>
</Root>';
DECLARE @xml3 xml = 
'<Root>
    <ThirdParty>
        <BureauGreen />
        <BureauRed />
        <BureauPurple />
        <BureauOrange />
        <BureauBlue />
    </ThirdParty>
</Root>';

DECLARE @temp TABLE (XmlData xml);

INSERT @temp VALUES (@xml1), (@xml2), (@xml3);

WITH cte AS
(
    SELECT n.value('local-name(.)', 'varchar(50)') nodeName
        FROM @temp t
        CROSS APPLY t.XmlData.nodes('/Root/ThirdParty/*') x(n)
)
SELECT nodeName, count(*) cnt
    FROM cte
    GROUP BY nodeName;

Output:

nodeName                                           cnt
-------------------------------------------------- -----------
BureauBlue                                         3
BureauGreen                                        2
BureauOrange                                       1
BureauPurple                                       2
BureauRed                                          3