T-sql select xml value - sql

Question

<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Header>
<Teste xmlns="http://google.com">
<Username></Username>
<Password></Password>
<Firma>Blabla</Firma>
</Teste>
</soap:Header>
<soap:Body>
-- Omitted
</soap:Body>
</soap:Envelope>
Having this xml in a column, how to retrieve the Firma value ? What's giving me more trouble is the "soap" namespaces that seem to be ruining my query's
This is what I was experimenting with, but not working as expected since the path is wrong
select ref.col.value('.','varchar(255)')
from my_View tbl
cross apply tbl.XMLColumn.nodes('Envelope/Header/Teste/Firma') as ref(col)

Answer 1

You must use namespaces in your Xquery
create table so_Test (XMLColumn xml)
go
insert so_Test
select '<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Header>
<Teste xmlns="http://google.com">
<Username></Username>
<Password></Password>
<Firma>Blabla</Firma>
</Teste>
</soap:Header>
<soap:Body>
</soap:Body>
</soap:Envelope>'
select XMLColumn.value('
declare namespace soap="http://schemas.xmlsoap.org/soap/envelope/";
declare namespace google="http://google.com";
/soap:Envelope[1]/soap:Header[1]/google:Teste[1]/google:Firma[1]', 'varchar(255)') as Firma from so_test
Result:
Firma
Blabla