FIRST_SIGNIFICANT_SUBDOMAIN

Description

Extract the "first valid subdomain" from the URL and return it. If it is illegal, an empty string will be returned.

Syntax

FIRST_SIGNIFICANT_SUBDOMAIN ( <url> )

Parameters

Parameter	Description
<url>	The URL from which the "first valid subdomain" needs to be extracted

Return value

The first valid subdomain in <url>.

Example

SELECT FIRST_SIGNIFICANT_SUBDOMAIN("www.baidu.com"),FIRST_SIGNIFICANT_SUBDOMAIN("www.google.com.cn"),FIRST_SIGNIFICANT_SUBDOMAIN("wwwwwwww")

+----------------------------------------------+--------------------------------------------------+-----------------------------------------+
| first_significant_subdomain('www.baidu.com') | first_significant_subdomain('www.google.com.cn') | first_significant_subdomain('wwwwwwww') |
+----------------------------------------------+--------------------------------------------------+-----------------------------------------+
| baidu                                        | google                                           |                                         |
+----------------------------------------------+--------------------------------------------------+-----------------------------------------+