Advanced ways using the Authorization Schemes inside APEX

The standard way to check the authorization is to select the correct scheme inside the security area:

What are authorization schemes and how do you create them?
http://docs.oracle.com/cd/E17556_01/doc/user.40/e15517/sec.htm#BABEDFGB
http://apps2fusion.com/at/64-kr/399-security-using-authorization-in-apex


There are a couple of hidden ways to check the authorization schemes differently to the standard way.

To check more then one authorization scheme with pl/sql use this hint from Denes Kubicek:
http://deneskubicek.blogspot.com/2009/05/checking-authorization-scheme-within.html

To check authorization schemes inside SQL follow this solution:
http://www.oracle.com/webfolder/technetwork/de/community/apex/tipps/repo-2/index.html

For those who do not understand German. Just create a simple function which let you use the authorization scheme function inside a sql statement:

create or replace function 

 my_check_auth(p_security_scheme in varchar2)

 return number is
begin
  if apex_util.public_check_authorization(p_security_scheme) 

  then
    return 1;
  else 
    return 0;
  end if;
end;

select 
  'VALID_USER' as return_val
from my_table
where col1 = 'NEW'
and (my_check_auth('AUTH_VALID_USER') = 1  

     or my_check_auth('AUTH_NEW_USER')
     )