CUT_TO_FIRST_SIGNIFICANT_SUBDOMAIN

Description

The CUT_TO_FIRST_SIGNIFICANT_SUBDOMAIN function extracts the effective part of a domain from a URL, including the top-level domain up to the "first significant subdomain". If the input URL is invalid, it returns an empty string.

Syntax

CUT_TO_FIRST_SIGNIFICANT_SUBDOMAIN(<url>)

Parameters

Parameter	Description
<url>	The URL string to be processed. Type: VARCHAR

Return Value

Returns VARCHAR type, representing the extracted domain part.

Special cases:

• If url is NULL, returns NULL
• If url is not a valid domain format, returns an empty string

Examples

1. Basic domain processing

SELECT cut_to_first_significant_subdomain('www.baidu.com');

+-----------------------------------------------------+
| cut_to_first_significant_subdomain('www.baidu.com') |
+-----------------------------------------------------+
| baidu.com                                           |
+-----------------------------------------------------+

2. Multi-level domain processing

SELECT cut_to_first_significant_subdomain('www.google.com.cn');

+---------------------------------------------------------+
| cut_to_first_significant_subdomain('www.google.com.cn') |
+---------------------------------------------------------+
| google.com.cn                                           |
+---------------------------------------------------------+

3. Invalid domain processing

SELECT cut_to_first_significant_subdomain('wwwwwwww');

+------------------------------------------------+
| cut_to_first_significant_subdomain('wwwwwwww') |
+------------------------------------------------+
|                                                |
+------------------------------------------------+