SELECT pk, xCol.query('/doc[sql:variable("@id") = 123]//section')   
FROM   docs

DECLARE	@r XML

SET	@r = '
<Reference>
  <Basic>
    <Book>A1.Hj1.JU9</Book>
  </Basic>
  <App>
    <A>AK9.HL9.J0</A>
    <A>A18.H.PJ69</A>
  </App>
  <Sub>
    <B>B13.H98.P9</B>
    <B>B18.HO9.JIU8</B>
  </Sub>
  <DI>
    <D>D23.HYT.P6R</D>
  </DI>
</Reference>
'
--1111111
SELECT node.query('fn:local-name(.)') AS NodeName, node.query('./text()') AS NodeValue
FROM @r.nodes(N'//*') T(node) 

SELECT	t.n.value('local-name(..)[1]', 'VARCHAR(100)') AS ParentNodeName,
	t.n.value('local-name(.)[1]', 'VARCHAR(100)') AS NodeName,
	t.n.value('text()[1]', 'VARCHAR(100)') AS NodeText
FROM	@r.nodes('/*/*/*') AS t(n)

DECLARE	@r1 XML
SET	@r1 = '
<Reference>
  <Basic Book="A1.Hj1.JU9" App="AK9.HL9.J0" />
</Reference>

DECLARE	@r2 XML
SET	@r2 = '
<Reference>
  <Basic App="test2" Name="test1" />
</Reference>

-- I have a function that pass both XMLs and attribute that I want to handle

exec HandleXml @r1, 'Book'
exec HandleXml @r2, 'Name'