Oracle isNumeric function

AFAIK there is no in-built function to do such but there are lots of ways to achieve the same using the functions already available.

Here is a list of some;

Option 1: Using to_number()
Attempt to convert the input/variable to a anumber.. if it succeeds then isNumeric is true otherwise false

CREATE OR REPLACE FUNCTION isNumeric (var in varchar) return char is

   dummy number;

begin

     select to_number(trim(var)) into dummy from dual; 

   if (dummy is null) then

      return '0';

   else

      return '1';

  end if;  

exception

   when others then

       return '0';

end;

/

Option 2: Using regex