Extract hostname from a URL

I found that there can be a lot of variation here, especially when running against a table of referrers. For this reason I created a SQL script that gets the host name from a web address that also covers all of the edge cases I found.

DECLARE @WebAddress varchar(300) = 'https://www.stevefenton.co.uk/2015/09/select-the-host-name-from-a-string-in-sql/'
SELECT 
    /* Get just the host name from a URL */
    SUBSTRING(@WebAddress,
        /* Starting Position (After any '//') */
        (CASE WHEN CHARINDEX('//', @WebAddress)= 0 THEN 1 ELSE CHARINDEX('//', @WebAddress) + 2 END),
        /* Length (ending on first '/' or on a '?') */
        CASE
            WHEN CHARINDEX('/', @WebAddress, CHARINDEX('//', @WebAddress) + 2) > 0 THEN CHARINDEX('/', @WebAddress, CHARINDEX('//', @WebAddress) + 2) - (CASE WHEN CHARINDEX('//', @WebAddress)= 0 THEN 1 ELSE CHARINDEX('//', @WebAddress) + 2 END)
            WHEN CHARINDEX('?', @WebAddress, CHARINDEX('//', @WebAddress) + 2) > 0 THEN CHARINDEX('?', @WebAddress, CHARINDEX('//', @WebAddress) + 2) - (CASE WHEN CHARINDEX('//', @WebAddress)= 0 THEN 1 ELSE CHARINDEX('//', @WebAddress) + 2 END)
            ELSE LEN(@WebAddress)
        END
    ) AS 'HostName'

This will handle...

• An address starting www. (i.e. no scheme)
• A address starting //
• Host names that terminate with a /
• Host names that terminate with a query string

Please use the below SQL code to extract the domain name:

DECLARE @WebUrl VARCHAR(35);
SET @WebUrl = 'http://stackoverflow.com/questions/ask?title=trim'

SELECT @WebUrl AS 'WebsiteURL',
       LEFT(SUBSTRING(@WebUrl, 
       (CASE WHEN CHARINDEX('//',@WebUrl)=0 
            THEN 5 
            ELSE  CHARINDEX('//',@WebUrl) + 2
            END), 35),
       (CASE 
       WHEN CHARINDEX('/', SUBSTRING(@WebUrl, CHARINDEX('//', @WebUrl) + 2, 35))=0 
       THEN LEN(@WebUrl) 
       else CHARINDEX('/', SUBSTRING(@WebUrl, CHARINDEX('//', @WebUrl) + 2, 35))- 1
       END)
       ) AS 'Domain';