Invalid Character in Email Address Check Query [SOLVED]

Question

I have been asked to identify a list of all email addresses on our system which contain invalid characters.
Acceptable characters are: 1-9, and a-z, and also '\','.','@'.
Is this something a regular expression would be able to handle?
I have made a start via:SELECT fu.user_id
     , fu.user_name
     , fu.email_address fu_email
  FROM applsys.fnd_user fu
WHERE (
           fu.email_address LIKE '%(%'
        OR fu.email_address LIKE '%)%'
        OR fu.email_address LIKE '%,%'
        OR fu.email_address LIKE '% %'
        OR fu.email_address LIKE '%+%'
        OR fu.email_address NOT LIKE '%@%'
        OR fu.email_address NOT LIKE '%.%'
       );But that seems pretty clunky, because I will have to add a new line for every character I want to search for. I have seen regular expressions being used for similar in the past, but I cannot tailor regexpressions to suit my need, because I find them really confusing.
Thanks
Message was edited by:
jimr

Answer 1

Thank you very much Frank and Anthony. We're not on Oracle 10 so the Translate option worked brilliantly - here's the answer, in case it is of help to anyone else who might have the same issue:
SELECT fu.user_id
     , fu.user_name
     , wlr.notification_preference
     , wlr.email_address
     , DECODE(
          TRANSLATE(
             LOWER(wlr.email_address)
           , '+0123456789abcdefghijklmnopqrstuvwxyz.@/-'
           , '+'
        , ' ', 'SPACE'
           TRANSLATE(
              LOWER(wlr.email_address)
            , '+0123456789abcdefghijklmnopqrstuvwxyz.@/-'
            , '+'
       ) invalid_character
  FROM applsys.fnd_user fu
     , applsys.wf_local_roles wlr
WHERE wlr.NAME = fu.user_name
   AND wlr.orig_system = 'PER'
   AND TRANSLATE(
          LOWER(wlr.email_address)
        , '+0123456789abcdefghijklmnopqrstuvwxyz.@/-'
        -- + followed by all the acceptable characters
       ,  '+'
       ) IS NOT NULL;