Read XML node attributes without using node name in SQL Server query

问题

I have XML stored into database with the different tag names but the same attribute names:

<book Category="Hobbies And Interests" PropertyName="C#" CategoryID="44" />
<sport Category="Hobbies And Interests" PropertyName="Cricket" CategoryID="46" />

These are just two examples but the tag name can be anything. I want to read "PropertyName" attribute from all node.

Is it possible? If yes then please anyone guide me.

回答1:

declare @xml xml

set @xml = '<book Category="Hobbies And Interests" PropertyName="C#" CategoryID="44" />
<sport Category="Hobbies And Interests" PropertyName="Cricket" CategoryID="46" />'

select T.c.value('@PropertyName', 'varchar(100)')
from @xml.nodes('/*') T(c)

If you expect that there can be elements without PropertyName attribute, you can use:

select T.c.value('@PropertyName', 'varchar(100)')
from @xml.nodes('/*[@PropertyName]') T(c)

If you also expect that elements can be nested, you can use:

select T.c.value('@PropertyName', 'varchar(100)')
from @xml.nodes('//*[@PropertyName]') T(c)

回答2:

Try this solution if you want to read PropertyName values from all nodes:

DECLARE @MyTable TABLE(
    ID INT IDENTITY(1,1) PRIMARY KEY,
    XmlCol XML NOT NULL
);
INSERT  @MyTable(XmlCol)
VALUES  (N'<book Category="Hobbies And Interests" PropertyName="C#" CategoryID="44" />');
INSERT  @MyTable(XmlCol)
VALUES  (N'<sport Category="Hobbies And Interests" PropertyName="Cricket" CategoryID="46" />');
INSERT  @MyTable(XmlCol)
VALUES  (N'<CocoJambo PropertyName="Aircraft carrier" Category="Hobbies And Interests"> <CocoJamboChild PropertyName="Airplane"/> </CocoJambo>');
INSERT  @MyTable(XmlCol)
VALUES  (N'<sport CategoryID="CocoJamboID" />');

SELECT  a.*,
        b.Node.value('(.)','NVARCHAR(100)') AS PropertyName_Value
FROM    @MyTable a
-- OUTER APPLY or CROSS APLLY
OUTER APPLY a.XmlCol.nodes('//@*[local-name(.)="PropertyName"]') b(Node);

Results:

ID          XmlCol                                    PropertyName_Value
----------- ----------------------------------------- ------------------
1           <book Category="Hobbies And Interes ...   C#
2           <sport Category="Hobbies And Intere ...   Cricket
3           <CocoJambo PropertyName="Aircraft c ...   Aircraft carrier
3           <CocoJambo PropertyName="Aircraft c ...   Airplane
4           <sport CategoryID="CocoJamboID" />        NULL

But if you want to show all rows that have XML framents with at least one PropertyName attribute then you could try:

SELECT  a.*
FROM    @MyTable a
WHERE   a.XmlCol.exist('//@*[local-name(.)="PropertyName"]')=1;

Results:

ID          XmlCol
----------- ----------------------------------------------------------------------------------
1           <book Category="Hobbies And Interests" PropertyName="C#" CategoryID="44" />
2           <sport Category="Hobbies And Interests" PropertyName="Cricket" CategoryID="46" />
3           <CocoJambo PropertyName="Aircraft carrier" Category="Hobbies And Interests"><CocoJ ...

来源：https://stackoverflow.com/questions/17857468/read-xml-node-attributes-without-using-node-name-in-sql-server-query

标签

sql-server

xml

xml-attribute