Question

Imagine I have some XML that looks like this:

DECLARE @xml XML
SET @xml = CAST(N'<row><id>1</id><a>b</a></row><row><id>2</id><a>x</a></row>' AS XML)

That is:

<row>
    <id>1</id>
    <a>b</a>
</row>
<row>
    <id>2</id>
    <a>x</a>
</row>

The id element is the key of each row, and it may be dynamic, so I have it stored in a variable:

DECLARE @idname NVARCHAR(MAX)
SET @idname = N'id'

I would like to have a resultset with two columns, the id value and the row’s contents.
I tried this:

SELECT node.value(N'xxx', N'NVARCHAR(MAX)') AS key, CAST(node.query(N'.') AS NVARCHAR(MAX)) AS value
FROM @xml.nodes(N'/row') AS roots(node)

The problem is, I don’t know what to put inside value, instead of xxx. I would like to be able to do something like:

node.value(@idname, N'VARCHAR(MAX))

So that my variable would be evaluated as an XPath expression, but I know it’s not possible. If I use instead:

node.value(N'sql:variable("@idname")', N'NVARCHAR(MAX)')

It will return the value that’s in the @idname variable, instead of evaluating it.

What I want to have is:

--------------------------------------

key           |value

--------------------------------------

1             |<id>1</id><a>b</a>

2             |<id>2</id><a>x</a>

So, is this possible at all?

Thanks!

Answer 1

select T.N.value('(*[local-name(.)=sql:variable("@idname")])[1]', 'int') as [key],
       T.N.query('*') as value
from @xml.nodes('/row') as T(N)