How to remove accents and all chars <> a..z in sql-server?

Question

I need to do the following modifications to a varchar(20) field:

1. substitute accents with normal letters (like è to e)
2. after (1) remove all the chars not in a..z

for example

'aèà?=.32s df' 

must become

'aeacsdf'

are there special stored functions to achieve this easily?

UPDATE: please provide a T-SQL not CLR solution. This is the workaround I temporarly did because it temporarly suits my needs, anyway using a more elegant approach would be better.

CREATE FUNCTION sf_RemoveExtraChars (@NAME nvarchar(50))
RETURNS nvarchar(50)
AS
BEGIN
  declare @TempString nvarchar(100)
  set @TempString = @NAME 
  set @TempString = LOWER(@TempString)
  set @TempString =  replace(@TempString,' ', '')
  set @TempString =  replace(@TempString,'à', 'a')
  set @TempString =  replace(@TempString,'è', 'e')
  set @TempString =  replace(@TempString,'é', 'e')
  set @TempString =  replace(@TempString,'ì', 'i')
  set @TempString =  replace(@TempString,'ò', 'o')
  set @TempString =  replace(@TempString,'ù', 'u')
  set @TempString =  replace(@TempString,'?', 'c')
  set @TempString =  replace(@TempString,'''', '')
  set @TempString =  replace(@TempString,'`', '')
  set @TempString =  replace(@TempString,'-', '')
  return @TempString
END
GO

Answer 1

The best way to achieve this is very simple and efficient :

SELECT 'àéê?hello!' Collate SQL_Latin1_General_CP1253_CI_AI

which outputs 'aeeohello!'

The string must not be unicode. If you have a nvarchar just cast it to varchar before using the collate.

Here is a function that answers the OP needs :

create function [dbo].[RemoveExtraChars] ( @p_OriginalString varchar(50) )
returns varchar(50) as
begin

  declare @i int = 1;  -- must start from 1, as SubString is 1-based
  declare @OriginalString varchar(100) = @p_OriginalString Collate SQL_Latin1_General_CP1253_CI_AI;
  declare @ModifiedString varchar(100) = '';

  while @i <= Len(@OriginalString)
  begin
    if SubString(@OriginalString, @i, 1) like '[a-Z]'
    begin
      set @ModifiedString = @ModifiedString + SubString(@OriginalString, @i, 1);
    end
    set @i = @i + 1;
  end

  return @ModifiedString

end

Then, the command:

select dbo.RemoveExtraChars('aèà?=.32s df')

outputs

aeacsdf