Help with XQuery

I am trying to query an XML Datatype column in SQL Server, but getting no data back, and I suspect the XQuery but don't know what I am doing wrong:

SELECT

nref.value('AdvTxnID[1]', 'integer') AdvTxnID,

nref.value('SvcSysCode[1]', 'varchar(2)') SvcSysCode

FROM

myData CROSS APPLY [xmldata].nodes('/AdvanceTxnDoc/AdvanceTxn') AS R(nref)

<AdvanceTxnDoc xmlns="http://GMAC.RFC.COM/RCG/XML/Schema/ALM.AdvanceTxnDoc">

<AdvanceTxn>

<AdvTxnID>4125281</AdvTxnID>

<SvcSysCode>MS</SvcSysCode>

<LoanID>8484664</LoanID>

<AdvTypeCode>P&amp;I</AdvTypeCode>

<AdvEffDate>2005-08-25T00:00:00</AdvEffDate>

<AdvTxnAmt>.04</AdvTxnAmt>

<TxnCrtDate>2005-08-19T00:00:00</TxnCrtDate>

</AdvanceTxn>

<TxnCount>1</TxnCount>

</AdvanceTxnDoc>

What am I doing wrong?

Need to declare namespace in your xquery. Two way to do it as following example:

declare @.x xml
set @.x =
N'<AdvanceTxnDoc xmlns="http://GMAC.RFC.COM/RCG/XML/Schema/ALM.AdvanceTxnDoc">
<AdvanceTxn>
<AdvTxnID>4125281</AdvTxnID>
<SvcSysCode>MS</SvcSysCode>
<LoanID>8484664</LoanID>
<AdvTypeCode>P&amp;I</AdvTypeCode>
<AdvEffDate>2005-08-25T00:00:00</AdvEffDate>
<AdvTxnAmt>.04</AdvTxnAmt>
<TxnCrtDate>2005-08-19T00:00:00</TxnCrtDate>
</AdvanceTxn>
<TxnCount>1</TxnCount>
</AdvanceTxnDoc>'

with xmlnamespaces(default 'http://GMAC.RFC.COM/RCG/XML/Schema/ALM.AdvanceTxnDoc')
SELECT
nref.value('AdvTxnID[1]', 'integer') AdvTxnID,
nref.value('SvcSysCode[1]', 'varchar(2)') SvcSysCode
FROM
@.x.nodes('/AdvanceTxnDoc/AdvanceTxn') AS R(nref)

SELECT
nref.value('declare default element namespace "http://GMAC.RFC.COM/RCG/XML/Schema/ALM.AdvanceTxnDoc"; AdvTxnID[1]', 'integer') AdvTxnID,
nref.value('declare default element namespace "http://GMAC.RFC.COM/RCG/XML/Schema/ALM.AdvanceTxnDoc"; SvcSysCode[1]', 'varchar(2)') SvcSysCode
FROM
@.x.nodes('declare default element namespace "http://GMAC.RFC.COM/RCG/XML/Schema/ALM.AdvanceTxnDoc";/AdvanceTxnDoc/AdvanceTxn') AS R(nref)

|||

Worked great. Thanks!

-Kory