sql server语言 - URL sql的子字符串域名

Question

我有一组数据:

<>之前www.google.com.sgwww.yahoo.com市场观察bing.combbc.co.uk之前

有的数据有www.，有的没有。有的有.com/.com.sg/.com.ul，有的没有。

我如何提取只是名称，例如google, yahoo, marketwatch, bing, bbc使用SQL?

Answer 1

使用MS SQL Server的CHARINDEX和SUBSTRING语法，你可以做一些像…

(故意过度分割，使每一步都很明显)

WITH
  url_start AS
(
  SELECT
    *,
    CASE WHEN LEFT(myURL, 4) = 'www.' THEN 4 ELSE 1 END AS d_start
  FROM
    myTable
)
,
  url_end
AS
(
  SELECT
    *,
    CASE WHEN
      CHARINDEX('.', myURL, d_start) = 0
    THEN
      LEN(myURL) + 1
    ELSE
      CHARINDEX('.', myURL, d_start)
    END as d_end
  FROM
    url_start
)
SELECT
  *,
  SUBSTRING(myURL, d_start, d_end - d_start) AS domain
FROM
  url_end

Answer 2

您可以使用SQL中的Replace函数来删除www.，如果它不存在，它将保留字符串原样。

Select Replace(URLColumn, 'www.','') as [CleanURLColumn]
From YourTable

编辑

对不起，我错过了结尾-根据您提供的示例数据，这将提取名称:

Select  Case
        When CharIndex('.', Replace(URL, 'www.','')) > 0 then
           Left(Replace(URL, 'www.',''), CharIndex('.',Replace(URL, 'www.',''))-1)
        Else
           Replace(URL, 'www.','')
        End as [CleanURL]
From dbo.YourTable

Answer 3

;with cte as
(
  select replace(URL, 'www.', '')+'.' as url
  from myTable
)
select
  left(url, charindex('.', url)-1)
from cte