如何使用 FLWOR 查询合并 XML 文件中元素的相应数据？

Question

Looking to "rebuild" a book node from the original data.

---

How is the title data merged, if that's the correct terminology, with the corresponding year data?

Assuming that the title and year are defined with the let operator.

output:

<b>
  <t>Everyday Italian Harry Potter XQuery Kick Start Learning XML</t>
  <y>2005 2005 2003 2003</y>
</b>

query:

xquery version "3.1";

for $doc in db:open("bookstore")

let $title := data($doc/bookstore/book/title)
let $year  := data($doc/bookstore/book/year)

return
    <b>
        <t>{$title}</t>
        <y>{$year}</y>
    </b>

data:

<bookstore>
  <book category="cooking">
    <title lang="en">Everyday Italian</title>
    <author>Giada De Laurentiis</author>
    <year>2005</year>
    <price>30.00</price>
  </book>
  <book category="children">
    <title lang="en">Harry Potter</title>
    <author>J K. Rowling</author>
    <year>2005</year>
    <price>29.99</price>
  </book>
  <book category="web">
    <title lang="en">XQuery Kick Start</title>
    <author>James McGovern</author>
    <author>Per Bothner</author>
    <author>Kurt Cagle</author>
    <author>James Linn</author>
    <author>Vaidyanathan Nagarajan</author>
    <year>2003</year>
    <price>49.99</price>
  </book>
  <book category="web">
    <title lang="en">Learning XML</title>
    <author>Erik T. Ray</author>
    <year>2003</year>
    <price>39.95</price>
  </book>
</bookstore>

Also tried wrapping the entire query with an element node and curly braces.

---

output:

<b>
  <title lang="en">Everyday Italian</title>
  <title lang="en">Harry Potter</title>
  <title lang="en">XQuery Kick Start</title>
  <title lang="en">Learning XML</title>
  <year>2005</year>
  <year>2005</year>
  <year>2003</year>
  <year>2003</year>
</b>

query:

xquery version "3.1";

<b>
{

for $doc in db:open("bookstore")

return ($doc/bookstore/book/title,$doc/bookstore/book/year)

}
</b>

but, returns as a single element. see also:

nested looping within Xquery results in a mismatch? and idioms

Answer 1

Not sure, but are you looking for something like this?

for $doc in db:open("bookstore")/bookstore/book
return (
for $book in $doc  
  let $title := data($book/title),
   $year := data($book/year)
  return(
<b>
<t>{$title}</t>
<y>{$year}</y>)
</b>)
)

Output:

<b>
  <t>Everyday Italian</t>
  <y>2005</y>)
</b>
<b>
  <t>Harry Potter</t>
  <y>2005</y>)
</b>
<b>
  <t>XQuery Kick Start</t>
  <y>2003</y>)
</b>
<b>
  <t>Learning XML</t>
  <y>2003</y>)
</b>