XPath must be a literal?

Question

I have a stored proc with a parameter which I want to have contain an XPath expression which can then be used to retrieve a value in a select, but the r.value(...) exception message says that I can only use literals.

Is this true or is there a way around this?

create proc MySproc
    @myxml    xml,
    @xpath    nvarchar(50)
as
begin
    select r.value(@xpath, 'nvarchar(100)') as 'demofield'
    from @myxml.nodes('/*') as records(r)
end

I have also tried things like r.value('sql:column("@xpath")', 'nvarchar(100)')

Answer 1

Ok, well ultimately I've put it all in a dynamic statement. Which, of course, has caused it's own troubles...