🧪 XQuery Example – Basic Queries to Extract XML Data

🧲 Introduction – Why Learn Through XQuery Examples?

XQuery is best understood by doing. It may look like XML or SQL at first, but its true power comes from seeing how you can navigate, filter, and return specific data from XML documents. In this article, we’ll explore practical XQuery examples that show how to retrieve, format, and output XML content—perfect for beginners getting hands-on with their first queries.

🎯 In this guide, you’ll learn:

• How to write basic XQuery statements
• How to use for, where, and return
• Examples of data filtering, value extraction, and formatting
• Real outputs from real XML files

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📄 Sample XML: books.xml

<catalog>
  <book id="101">
    <title>Learn XQuery</title>
    <author>Jane Doe</author>
    <price>499</price>
  </book>
  <book id="102">
    <title>Advanced XML</title>
    <author>John Smith</author>
    <price>699</price>
  </book>
</catalog>

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🧾 Example 1 – Get All Book Titles

for $b in doc("books.xml")//book
return $b/title

✅ Output:

<title>Learn XQuery</title>
<title>Advanced XML</title>

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🔍 Example 2 – Filter Books with Price > 500

for $b in doc("books.xml")//book
where $b/price > 500
return $b/title

✅ Output:

<title>Advanced XML</title>

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💬 Example 3 – Return Titles as Plain Text

for $b in doc("books.xml")//book
return string($b/title)

✅ Output:

Learn XQuery
Advanced XML

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📝 Example 4 – Format Custom Output with Author and Price

for $b in doc("books.xml")//book
return 
  <info>
    <title>{$b/title/text()}</title>
    <author>{$b/author/text()}</author>
    <price>{$b/price + 100}</price>
  </info>

✅ Output:

<info>
  <title>Learn XQuery</title>
  <author>Jane Doe</author>
  <price>599</price>
</info>

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🔁 Example 5 – Use let for Local Variables

for $b in doc("books.xml")//book
let $t := $b/title/text()
let $p := $b/price
return <summary>{$t} costs ₹{$p}</summary>

✅ Output:

<summary>Learn XQuery costs ₹499</summary>
<summary>Advanced XML costs ₹699</summary>

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🔤 Example 6 – Sort Books Alphabetically by Title

for $b in doc("books.xml")//book
order by $b/title
return $b/title

✅ Output:

<title>Advanced XML</title>
<title>Learn XQuery</title>

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🧠 Example 7 – Condition-Based Output

for $b in doc("books.xml")//book
return
  if ($b/price > 500) then
    <premium>{$b/title}</premium>
  else
    <budget>{$b/title}</budget>

✅ Output:

<budget>Learn XQuery</budget>
<premium>Advanced XML</premium>

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✅ Best Practices

• ✔️ Use for, where, and return to build FLWOR expressions
• ✔️ Wrap output in XML tags for structured returns
• ✔️ Use let to store intermediate variables
• ✔️ Use XPath within XQuery to drill down into XML nodes
• ❌ Don’t forget doc("file.xml") when querying external documents

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📌 Summary – Recap & Next Steps

These XQuery examples show how easy it is to query and manipulate XML. With just a few lines, you can extract values, format output, and even perform calculations or apply conditions.

🔍 Key Takeaways:

• XQuery reads and processes XML using familiar looping and filtering logic
• You can return XML, plain text, or dynamic data
• Perfect for working with catalogs, APIs, feeds, and content systems

⚙️ Real-world relevance: Used in dashboards, reporting tools, XML APIs, publishing pipelines, and enterprise data platforms.

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❓ FAQs – XQuery Examples

❓ How do I access an XML file in XQuery?
✅ Use doc("filename.xml") to load the XML content.

❓ Can I return both XML and text?
✅ Yes. XQuery can mix both as output, but XML is the default.

❓ Can I perform math in XQuery?
✅ Absolutely. Use operators like +, -, div, mod.

❓ What’s the difference between string() and .text()?
✅ string() converts to a string; .text() extracts text node content.

❓ Can XQuery work across multiple XML files?
✅ Yes. Use multiple doc() calls or a collection.

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