Query inside WITH XMLNAMESPACE clause - sql-server

Question

is it possible to get some data of the namespaces in the result xml of FOR XML Clause
from database
e.g.
WITH XMLNAMESPACES ('uri1' as ns1,
'uri2' as ns2,
DEFAULT 'uri2')
SELECT ProductID,
Name,
Color
FROM Production.Product
WHERE ProductID=316 or ProductID=317
FOR XML RAW ('ns1:Product'), ROOT('ns2:root'), ELEMENTS
RESULTS :
<ns2:root xmlns="uri2" xmlns:ns2="uri2" xmlns:ns1="uri1">
<ns1:Product>
<ProductID>316</ProductID>
<Name>Blade</Name>
</ns1:Product>
<ns1:Product>
<ProductID>317</ProductID>
<Name>LL Crankarm</Name>
<Color>Black</Color>
</ns1:Product>
</ns2:root>
WHAT IF I'D LIKE TO GET THE VALUE OF FROM INSIDE DATABASE ?
something like this :
WITH XMLNAMESPACES ('uri1' as ns1,
**(SELECT namespace from tableName)** as ns2,
DEFAULT 'uri2')

Answer 1

This type of thing is possible with dynamic SQL but obviously that has its own issues. Please read this excellent article from Erland Sommarskog on that topic.
DECLARE #productId INT = 317
DECLARE #sql NVARCHAR(MAX) = 'WITH XMLNAMESPACES ( ''uri1'' as ns1, ''#yourNamespace'' as ns2, DEFAULT ''uri2'' )
SELECT
ProductID,
Name,
Color
FROM Production.Product
WHERE ProductID = #productId
FOR XML RAW (''ns1:Product''), ROOT(''ns2:root''), ELEMENTS'
SET #sql = REPLACE( #sql, '#yourNamespace', 'ns2' )
EXEC sp_executesql #sql, N'#productId INT', #productId
Re your FOR XML AUTO question, AUTO is driven by the object and column names, so you can take control of this using aliases, eg
;WITH XMLNAMESPACES( DEFAULT 'uri2', 'ns2' AS ns2, 'uri1' AS ns1 )
SELECT
ProductID,
Name,
Color
FROM Production.Product AS "ns1:productO"
WHERE ProductID = 317
FOR XML AUTO
I personally prefer FOR XML PATH for this as you have complete control and everything is explict ( ie you have to specify namespace and element or attribute, rather than it being inferred by AUTO ).
;WITH XMLNAMESPACES( DEFAULT 'uri2', 'ns2' AS ns2, 'uri1' AS ns1 )
SELECT
ProductID AS "#ProductID",
Name AS "#Name",
Color AS "#Color"
FROM Production.Product AS "ns1:productO"
WHERE ProductID = 317
FOR XML PATH('ns1:product0')
Probably a separate question though ; )
HTH