How to remove all non-alphabetic characters from string in SQL Server?

Create a function to solve the given problem:

CREATE FUNCTION RemoveNonAlphaCharacters

(@StringName VARCHAR(1000))

RETURNS VARCHAR(1000)

AS

BEGIN

     DECLARE @KeepValues as Varchar(50)

     SET @KeepValues='%[^a-z]%'

     WHILE PATINDEX(@KeepValues,@StringName)>0

     SET @StringName= STUFF(@StringName,PATINDEX(@KeepValues,@StringName),1,'')

     RETURN @StringName

END

Now, Call the Function as below

select DBO.RemoveNonAlphaCharacters('fefwsAA1456sdfsf')

output : fefwsAAsdfsf