How to remove special characted and numerics in sql server

Question

Hi Developers,

i need to remove special characters and numerics in my sql query.

my code is 

    DECLARE @USErId AS VARCHAR(100)='[email protected]'

    SELECT DISTINCT

  CASE 
       WHEN ISNULL(@USERID,'') LIKE '%t-mobile.com%' 
       THEN REPLACE(REPLACE(REPLACE(@USERID,SUBSTRING (@USERID,CHARINDEX( '@', @USERID ) + 1, LEN(@USERID)),''),'@',''),'.','') 
  ELSE
       SUBSTRING(@USErId, 1, CHARINDEX('.', @USERID)-1) +REPLACE(SUBSTRING(SUBSTRING(@USERID, CHARINDEX('.', @USERID) + 1, 1000), 1,
       CHARINDEX('@', SUBSTRING(@USERID, CHARINDEX('.', @USERID) + 1, 1000))-1),
       REVERSE(LEFT(reverse(SUBSTRING(SUBSTRING(@USErId, CHARINDEX('.', @USERID) + 1, 1000), 1,
       CHARINDEX('@', SUBSTRING(@USERID, CHARINDEX('.', @USERID) + 1, 1000))-1)),
       PATINDEX('%[0-9][^0-9]%', reverse(SUBSTRING(SUBSTRING(@USERID, CHARINDEX('.', @USERID) + 1, 1000), 1,
       CHARINDEX('@', SUBSTRING(@USERID, CHARINDEX('.', @USERID) + 1, 1000))-1)) ))),'')
       END AS 'Original Owners',
  CASE 
       WHEN ISNULL(@USERID,'') LIKE '%t-mobile.com%'
       THEN  ISNULL(@USERID,'')
  ELSE ''
       END AS 'OriginalOwnerEmail'

My expected output = paulraj

if anyone know how to do this kindly suggest me to done this task

 

Regards & Thanks

Paul.S