CREATE PROCEDURE "DBA"."__CharToOem"(in invar char(255),out outvar char(255)) external name 'CharToOemA@user32.dll';

CREATE FUNCTION "DBA"."_CharToOem"(in str varchar(255))
returns varchar(255) begin
  /* Перекодировка 1251 --> 866 через API */
  declare rc varchar(255);
  if str is null then return str
  end if
  ;
  call __CharToOem(str,rc);
  return rc
end;

select _CharToOem('Тест')