How to use XQuery to extract specific XML records and output in comma delimited format?

I'm trying to extract only <xref> data along with their book IDs using a XQuery (I'm new to this).

Here is the input data:

  <book id="6636551">
    <master_information>
        <book_xref>
            <xref type="Fiction" type_id="1">72771KAM3</xref>
            <xref type="Non_Fiction" type_id="2">US72771KAM36</xref>
        </book_xref>
    </master_information>
    <book_details>
        <price>24.95</price>
        <publish_date>2000-10-01</publish_date>
        <description>An in-depth look at creating applications with XML.</description>
    </book_details>
  </book>
  <book id="119818569">
    <master_information>
        <book_xref>
            <xref type="Fiction" type_id="1">070185UL5</xref>
            <xref type="Non_Fiction" type_id="2">US070185UL50</xref>
        </book_xref>
    </master_information>
    <book_details>
        <price>19.25</price>
        <publish_date>2002-11-01</publish_date>
        <description>A former architect battles corporate zombies, 
  an evil sorceress, and her own childhood to become queen 
  of the world.</description>
    </book_details>
  </book>
  <book id="119818568">
  <master_information>
        <book_xref>
            <xref type="Fiction" type_id="1">070185UK7</xref>
            <xref type="Non_Fiction" type_id="2">US070185UK77</xref>
        </book_xref>
    </master_information>
    <book_details>
        <price>5.95</price>
        <publish_date>2004-05-01</publish_date>
        <description>After the collapse of a nanotechnology 
  society in England, the young survivors lay the 
  foundation for a new society.</description>
    </book_details>
  </book>
  <book id="119818567">
    <master_information>
        <book_xref>
            <xref type="Fiction" type_id="1">070185UJ0</xref>
            <xref type="Non_Fiction" type_id="2">US070185UJ05</xref>
        </book_xref>
    </master_information>
    <book_details>
        <price>4.95</price>
        <publish_date>2000-09-02</publish_date>
        <description>When Carla meets Paul at an ornithology 
  conference, tempers fly as feathers get ruffled.</description>
    </book_details>
  </book>

Expected output format 1:

  <book id="6636551">
    <master_information>
        <book_xref>
            <xref type="Fiction" type_id="1">72771KAM3</xref>
            <xref type="Non_Fiction" type_id="2">US72771KAM36</xref>
        </book_xref>
    </master_information>
  </book>

XQuery that I'm using for format 1:

  for$x in //book_xref/xref
  return $x

Question for format 1: I tried including book id separately so that it's included in the output but it doesn't match the expected format as I mentioned above. How do I get the book id to be fetched as well in the output per the format?

Expected output format 2 (comma delimited):

  book_id, xref_type, xref_type_id, xref
  6636551, Fiction, 1, 72771KAM3
  6636551, Non_Fiction, 2, US72771KAM36
  119818569, Fiction, 1, 070185UL5
  119818569, Non_Fiction, 2, US070185UL50
  etc.

Question for format 2: How can I get output in comma delimited format through XQuery? Do I need to stick to XSLT for that?

I appreciate your response.