select ID, GetMeDomainNameFromUrl('http://www.sql.ru/forum/actualpost.aspx?bid=2') from  Table

select distinct REPLACE(URL,  '/', '') as URL from (
select REPLACE(OUT,  'http://', '') as url from (
WITH T
AS (SELECT
        url AS STR
    FROM
        pars_tab
        where Url like 'http://%')
SELECT
    substring(str from 1 for position('/', str, 8)) as out
FROM
T
 )
union
select REPLACE(out,  'https://', '') as url from (
WITH T1
AS (SELECT
        substring(URL from 9 for CHAR_LENGTH(url)-8) AS STR
    FROM
        pars_tab
        where Url like 'https://%')
SELECT
    substring(str from 1 for position('/', str, 9)) as out
FROM
T1 ))
order by 1