How can I use a WITH XMLNAMESPACES clause with correlated queries?

Question

I'm trying to use the FOR XML feature of SQL Server to generate some XML, with some specific namespaces.

My target XML should look something like:

<ns1:CustomerInvoices xmlns:ns1="urn:example.com:Invoice:01.00">
  <CustomerInvoice>
    <Header>
      <OrderDate>2001-11-13T00:00:00</OrderDate>
      <SalesOrderNumber>SO44643</SalesOrderNumber>
    </Header>
    <Lines>
      <LineTotal>3578.270000</LineTotal>
      <UnitPrice>3578.2700</UnitPrice>
      <OrderQty>1</OrderQty>
    </Lines>
  </CustomerInvoice>
  <CustomerInvoice>...(abbreviated)...</CustomerInvoice>
</ns1:CustomerInvoices>

The problem I have, is that when I use the WITH XMLNAMESPACES clause, is the namespace declaration appears on lots of the child nodes, which the third party consumer of this XML would "prefer not to get", i.e. I'm doing something like:

Use AdventureWorks2008

;WITH XMLNAMESPACES ('urn:example.com:Invoice:01.00' as ns1)

SELECT      (SELECT     hdr.OrderDate,
                        hdr.SalesOrderNumber
            FOR XML PATH (''), TYPE) AS Header,
            (SELECT     line.LineTotal,
                        line.UnitPrice,
                        line.OrderQty

            FROM        Sales.SalesOrderDetail  AS line

            WHERE       line.SalesOrderID = hdr.SalesOrderID
            FOR XML PATH (''), TYPE) AS Lines

FROM        Sales.SalesOrderHeader  AS hdr

WHERE       hdr.ModifiedDate = '2001-11-20'

FOR XML PATH('CustomerInvoice'), ROOT('ns1:CustomerInvoices') 

Which gives:

<ns1:CustomerInvoices xmlns:ns1="urn:example.com:Invoice:01.00">
  <CustomerInvoice>
    <Header>
      <OrderDate xmlns:ns1="urn:example.com:Invoice:01.00">2001-11-13T00:00:00</OrderDate>
      <SalesOrderNumber xmlns:ns1="urn:example.com:Invoice:01.00">SO44643</SalesOrderNumber>
    </Header>
    <Lines>
      <LineTotal xmlns:ns1="urn:example.com:Invoice:01.00">3578.270000</LineTotal>
      <UnitPrice xmlns:ns1="urn:example.com:Invoice:01.00">3578.2700</UnitPrice>
      <OrderQty xmlns:ns1="urn:example.com:Invoice:01.00">1</OrderQty>
    </Lines>
  </CustomerInvoice>
  <CustomerInvoice>...(abbreviated)...</CustomerInvoice>
</ns1:CustomerInvoices>

Is it possible to tweak the query to get the namespaces correct, or will I have to load this into "something else" to remove the redundant namespace declarations?

Solution

You're not alone.

http://connect.microsoft.com/SQLServer/feedback/details/265956/suppress-namespace-attributes-in-nested-select-for-xml-statements

I would suggest upvoting that improvement.

There is a work around listed at the connect site above:

http://www.olcot.co.uk/sql-blogs/suppressing-namespace-attributes-in-nested-select-statements-when-using-for-xml-workaround

APPEND/EDIT:

The second link I posted above is now dead.

Here is a different link:

http://www.sqlservercentral.com/blogs/rocks/2012/08/28/suppressing-namespace-attributes-in-nested-select-statements-when-using-for-xml-workaround/