Using XQuery in Sql Server to Parse XML Complex types

Question

I have the following XML :

<Feed>
  <FeedId>10</FeedId>
   <Component>
     <Date>2011-10-01</Date>
     <Date>2011-10-02</Date>
   </Component>
</Feed>

Now if possible I would like to parse the XML into sql so it's serialized into the following relational data:

FeedId   Component_Date
10       2011-10-01
10       2011-10-02

However using the following SQL:

DECLARE @XML XML;
DECLARE @XMLNodes XML;
SET @XML = '<Feed><FeedId>10</FeedId><Component><Date>2011-10-01</Date><Date>2011-10-02</Date></Component></Feed>';

SELECT  t.a.query('FeedId').value('.', 'INT') AS FeedId
    ,t.a.query('Component/Date').value('.', 'VARCHAR(80)') AS [Component_Date]
    FROM @XML.nodes(' /Feed') AS t(a)

The closest I get is :

FeedId  Component_Date
10  2011-10-012011-10-02

So the date values appear in the same row, is it possible to achieve what I want using XQuery?

Answer 1

You need a second call to .nodes() since you have multiple entries inside your XML - try this:

SELECT  
    t.a.value('(FeedId)[1]', 'INT') AS FeedId,
    c.d.value('(.)[1]', 'DATETIME') AS [Component_Date]
FROM 
    @XML.nodes('/Feed') AS t(a)
CROSS APPLY
    t.a.nodes('Component/Date') AS C(D)

Gives me an output of:

FeedId  Component_Date
  10    2011-10-01 00:00:00.000
  10    2011-10-02 00:00:00.000

Answer 2

OK, I can do it using OPENXML method:

eclare @idoc int
DECLARE @XML XML;
DECLARE @XMLNodes XML;
SET @XML = '<Feed><FeedId>10</FeedId><Component><Date>2011-10-01</Date><Date>2011-10-02</Date></Component></Feed>';

exec sp_xml_preparedocument @idoc OUTPUT, @XML
-- SELECT stmt using OPENXML rowset provider
SELECT *
FROM   OPENXML (@idoc, '/Feed/Component/Date',1)
         WITH (
                FeedId              Int         '../../FeedId',
                ComponentDate       Date         'text()'
               )