HTML Extraction Functions
=========================
These functions extract data from HTML documents.
html_extract_text
-----------------
Extract text content from HTML.
**Syntax:**
.. code-block:: sql
html_extract_text(html)
html_extract_text(html, xpath)
**Parameters:**
- ``html`` (VARCHAR or HTML): The HTML content
- ``xpath`` (VARCHAR, optional): XPath expression to match specific elements
**Returns:** VARCHAR - The extracted text content.
**Examples:**
.. code-block:: sql
-- Extract all text
SELECT html_extract_text('Hello World
');
-- Result: "Hello World"
-- Extract specific element
SELECT html_extract_text('Title
Body
', '//h1');
-- Result: "Title"
.. note::
When using XPath, only the first matching element's text is returned.
html_extract_links
------------------
Extract all hyperlinks from HTML with metadata.
**Syntax:**
.. code-block:: sql
html_extract_links(html)
**Returns:** LIST
**Example:**
.. code-block:: sql
SELECT html_extract_links(
'HomeAbout'
);
-- Result: [
-- {text: "Home", href: "/home", title: "Home Page", line_number: 1},
-- {text: "About", href: "/about", title: NULL, line_number: 1}
-- ]
-- Unnest to get individual links
SELECT (unnest(html_extract_links(html))).href as url
FROM read_html_objects('page.html');
html_extract_images
-------------------
Extract all images from HTML with metadata.
**Syntax:**
.. code-block:: sql
html_extract_images(html)
**Returns:** LIST
**Example:**
.. code-block:: sql
SELECT html_extract_images(
'
'
);
-- Result: [{alt: "A photo", src: "photo.jpg", title: NULL, width: 800, height: 600, line_number: 1}]
html_extract_tables
-------------------
Extract HTML tables as rows (table function).
**Syntax:**
.. code-block:: sql
SELECT * FROM html_extract_tables(html)
**Returns:** TABLE(table_index INTEGER, row_index INTEGER, columns VARCHAR[])
**Example:**
.. code-block:: sql
SELECT * FROM html_extract_tables(
''
);
-- Result:
-- table_index | row_index | columns
-- 0 | 0 | ["Name", "Age"]
-- 0 | 1 | ["John", "30"]
html_extract_table_rows
-----------------------
Extract table data as structured rows.
**Syntax:**
.. code-block:: sql
html_extract_table_rows(html)
**Returns:** LIST - Structured table data.
html_extract_tables_json
------------------------
Extract tables with rich JSON structure including headers.
**Syntax:**
.. code-block:: sql
html_extract_tables_json(html)
**Returns:** LIST
html_escape
-----------
Escape HTML special characters.
**Syntax:**
.. code-block:: sql
html_escape(text)
**Parameters:**
- ``text`` (VARCHAR): Text to escape
**Returns:** VARCHAR - Text with HTML entities escaped.
**Example:**
.. code-block:: sql
SELECT html_escape('Hello & World
');
-- Result: "<p>Hello & World</p>"
html_unescape
-------------
Decode HTML entities to text.
**Syntax:**
.. code-block:: sql
html_unescape(text)
**Parameters:**
- ``text`` (VARCHAR): Text with HTML entities
**Returns:** VARCHAR - Decoded text.
**Example:**
.. code-block:: sql
SELECT html_unescape('<p>Hello & World</p>');
-- Result: "Hello & World
"
parse_html
----------
Parse an HTML string into the HTML type.
**Syntax:**
.. code-block:: sql
parse_html(content)
**Parameters:**
- ``content`` (VARCHAR): HTML string to parse
**Returns:** HTML - Parsed HTML document.
**Example:**
.. code-block:: sql
SELECT parse_html('Hello
');