如何使用 Xquery 用 XML 节点包装每个 return 结果？

Question

也许可以在每个 return 周围添加一个额外的 for 循环，然后用一个节点包装结果？

修改 w3 学校样本 query:

nicholas@mordor:~/flwor$ 
nicholas@mordor:~/flwor$ basex bookstore.category.name.xq 
<xml>
  <category>cooking</category>
  <title>Everyday Italian</title>
  <category>children</category>
  <title>Harry Potter</title>
  <category>web</category>
  <title>Learning XML</title>
  <category>web</category>
  <title>XQuery Kick Start</title>
</xml>nicholas@mordor:~/flwor$ 
nicholas@mordor:~/flwor$ 
nicholas@mordor:~/flwor$ cat bookstore.category.name.xq 

xquery version "3.1";


<xml>
{
for $x in db:open("bookstore")/bookstore/book
order by $x/title
return (<category>{data($x/@category)}</category>,<title>{data($x/title)}</title>)
}
</xml>
nicholas@mordor:~/flwor$

如何用 book 元素包装每个结果？

xml样本数据：

<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>

来自 w3schools 网站。

Answer 1

应该这样做：

<xml>
{
for $x in db:open("bookstore")/bookstore/book
let $category := data($x/@category)
return (
for $book in $x  
  let $title := data($book/title)
  return(
<book>
<category>{$category}</category><title>{$title}</title>)
</book>)
)
}
</xml>

输出：

<xml>
  <book>
    <category>cooking</category>
    <title>Everyday Italian</title>)
</book>
  <book>
    <category>children</category>
    <title>Harry Potter</title>)
</book>
  <book>
    <category>web</category>
    <title>XQuery Kick Start</title>)
</book>
  <book>
    <category>web</category>
    <title>Learning XML</title>)
</book>
</xml>

如何使用 Xquery 用 XML 节点包装每个 return 结果？

How to wrap each return result with an XML node using Xquery?

xml

xpath

xquery

flwor

basex