SQL Server XML XQuery select where clause attribute

Question

I have a table with the following content

Id | Guid                                 | XmlDefinitionId
 1 | 5a0bfc84-13ec-4497-93e0-655e57d4b482 | 1
 2 | e28e786b-0856-40b6-8189-0fbd68aa3e45 | 1

And in another table the following XML structure stored:

<ActionActivity DisplayName="DisplayName 1" IsSkipped="False" Id="5a0bfc84-13ec-4497-93e0-655e57d4b482">...</ActionActivity>
<p:Sequence DisplayName="Prerequisites">
    <ActionActivity DisplayName="Inner DisplayName 1" IsSkipped="False" Id="e28e786b-0856-40b6-8189-0fbd68aa3e45">...</ActionActivity>
</p:Sequence>
<ActionActivity DisplayName="DisplayName 2" IsSkipped="False" Id="dcc936dd-73c9-43cc-beb4-c636647d4851">...</ActionActivity>

The table containing the XML have the following structure:

Id | XML
1  | (XML Structure defined above here)

Based on the Guid I want to show the displayname. At the moment I have the following query that returns null at the moment. Later I want for every guid from the first table show the displayname.

SELECT 
      Workflow
      ,CAST(Workflow as XML).value('data(//ActionActivity[@Id="73c9-43cc-beb4-c636647d4851"])[1]', 'nvarchar(50)') as displayname
  FROM SerializedData

Anyone ideas to show the displayname with a sql query?

Answer 1

Assuming that the XML stored in XML typed column, you can do this way -otherwise you'll need to CAST the column to XML- :

SELECT
    g.guid, x.display_name
FROM GuidTable g
     INNER JOIN 
     (
        SELECT 
            t.id as 'xml_id'
            , c.value('@Id', 'varchar(max)') as 'guid'
            , c.value('@DisplayName', 'varchar(max)') as 'display_name'
        FROM XmlTable t
            CROSS APPLY t.xml.nodes('//ActionActivity') as aa(c)
     ) x on x.guid = g.guid and x.xml_id = g.xmldefinitionid

Basically, above query shred the XML at ActionActivity node. And then joins shredded data with GuidTable on guid and xmldefinitionid columns.

output :

SQL Fiddle