此 xquery 脚本中的语法错误是什么?

问题描述：

我是 XQuery 的初学者，正在尝试做一些简单的练习来学习它.但是我试图组合的这个最新查询拒绝运行，给我一个语法错误.

I'm a beginner to XQuery, trying to do some simple exercises to learn it. But this latest query I'm trying to put together refuses to run, giving me a syntax error.

这是我的 XQuery:

This is my XQuery:

<HTML>
<HEAD><TITLE>Alphabetical Cities Lists</TITLE></HEAD>
<BODY>
{
  for $indcode in (65 to 70)
  let $indlet := codepoints-to-string($indcode)
  return 
     <H1> {$indlet} LIST </H1>
     {
       for $cit in doc("mydoc.xml")/CITIES/ENTITY
       where starts-with($cit/NAME,$indlet)
       order by $cit/NAME
       return <LI>{$cit/NAME}</LI>
     }
     </OL>
} 
</BODY>
</HTML>

这是我的 XML 文件 mydoc.xml 的一个子集:

And this is a subset of my XML file mydoc.xml:

<CITIES>
  <ENTITY>
    <NAME>Hastings</NAME>
    <CITYCOD>230</CITYCOD>
    <CNTYCOD>01</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Tilden</NAME>
    <CITYCOD>487</CITYCOD>
    <CNTYCOD>02</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Alliance</NAME>
    <CITYCOD>008</CITYCOD>
    <CNTYCOD>07</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Hemingford</NAME>
    <CITYCOD>236</CITYCOD>
    <CNTYCOD>07</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Ainsworth</NAME>
    <CITYCOD>003</CITYCOD>
    <CNTYCOD>09</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Kearney</NAME>
    <CITYCOD>269</CITYCOD>
    <CNTYCOD>10</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Oakland</NAME>
    <CITYCOD>358</CITYCOD>
    <CNTYCOD>11</CNTYCOD>
  </ENTITY>
  <ENTITY>
    <NAME>Eagle</NAME>
    <CITYCOD>159</CITYCOD>
    <CNTYCOD>13</CNTYCOD>
  </ENTITY>
</CITIES>

我想要它做的是打印出一个简单的 HTML 文档，其中包含这些城市名称的几个列表，由它们开头的字母(A 到 F)分隔.

What I want it to do is print out a simple HTML document with several lists of these city names, broken out by the letter they start with (A to F).

但是当我尝试在这个网站上运行这个时，它给了我这个错误:

But when I try running this out on this site, it gives me this error:

查询:<>，第 9 行，第 6 列:[XPST0003] 语法错误，意外的'{'"，需要'}'"

我不知道为什么这么说.我已经检查并检查过，但我的花括号似乎都正确匹配.任何人都可以看到问题是什么?谢谢.

I have no idea why it says that. I've checked and checked, but my curly braces all seem properly matched. Can anyone see what the problem is? Thanks.

答

这是一个常见的错误.

您需要在

和节点之间放置 , .

You need to place a , between the <H1> and <OL> nodes.

单个节点是一个 XQuery 表达式(就像直接元素构造函数中的多个节点一样).返回表达式必须是表达式.在这种情况下，您要返回两个节点.每个节点都是一个项目，因此为了返回它们，您需要按顺序连接两个节点.

A single node is an XQuery expression (as are multiple nodes inside a direct element constructor). The return expression must be an expression. In this case you want to return two nodes. Each node is a single item and so in order to return them both you need to concatenate the two nodes in a sequence.

查询将如下所示:

<HTML>
<HEAD><TITLE>Alphabetical Cities Lists</TITLE></HEAD>
<BODY>
{
  for $indcode in (65 to 70)
  let $indlet := codepoints-to-string($indcode)
  return 
     (<H1> {$indlet} LIST </H1>,
     <OL>
     {
       for $cit in doc("mydoc.xml")/CITIES/ENTITY
       where starts-with($cit/NAME,$indlet)
       order by $cit/NAME
       return <LI>{$cit/NAME}</LI>
     }
     </OL>)
} 
</BODY>
</HTML>

此 xquery 脚本中的语法错误是什么?

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