Construct xml with variable node names in TSQL - sql-server

Question

In my application I am running a rather complex query using FOR XML PATH() to construct an xml result. I am using this query in several stored procedures but each the root node and the first level node names are different. What I would like to do is create a scalar user defined function that takes the two node names as parameters and returns the correct xml. The expected output would look like this:
<{root node name}>
<{first level node name} attr1="value1" attr2="value2">
<detail attr1="value3">
<error code="1" descr="some error"/>
<error code="3" descr="some other error"/>
</detail>
</{first level node name}>
<error code="4" descr="yet another error"/>
</{root node name}>
With {root node name} and {first level node name} being passed as parameters
I know I can use dynamic SQL to do this but it can be very cumbersome and I would like to avoid it. I could also do it easily in C# or using XSLT but I need to do this entirely in SQL as it will be called from SQL Service broker handlers.
Unfortunately FOR XML PATH requires a literal for the node name. I also tried creating the xml with known generic node names and then trying to replace them using XQuery, but that also requires literals. Both the XQuery has to be a literal and the node names used in node constructors need to be literals as well (cannot use sql:variable())
Is there any way create XML with dynamic node names?

Answer 1

As the elements names are built out of the result set's column names this cannot work (other than dynamic SQL or CLR), but there is rescue:
DECLARE #rowName NVARCHAR(10)=N'TheRow';
DECLARE #rootName NVARCHAR(10)=N'TheRoot';
DECLARE #OutputXml XML=
CAST(
REPLACE(REPLACE(
CAST((SELECT TOP 2 [name],[type]
FROM sys.objects
FOR XML PATH(N'ThisIsAStringOnlyUsedAsRowElementName')
,ROOT(N'TheSameIdeaForTheRootName')
,TYPE) AS NVARCHAR(MAX))
,N'ThisIsAStringOnlyUsedAsRowElementName',#rowName)
,N'TheSameIdeaForTheRootName',#rootName) AS XML);
SELECT #outputXML;
The result
<TheRoot>
<TheRow>
<name>spt_fallback_db</name>
<type>U </type>
</TheRow>
<TheRow>
<name>spt_fallback_dev</name>
<type>U </type>
</TheRow>
</TheRoot>
In general I'd avoid string manipulations on an XML (due to possible side effects and performance impact). But I think this is a legit workaround...