ORACLE IS_NUMBER FUNCTION

CREATE OR REPLACE FUNCTION is_number(char_in VARCHAR2) RETURN NUMBER IS
BEGIN
FOR x IN 1 .. LENGTH(char_in) LOOP
— remove , & .
IF SUBSTR(char_in,x,1) in (’,’ , ‘.’ , ‘ ‘) THEN
RETURN 0;
END IF;
END LOOP;

IF TO_NUMBER(char_in,’9999999′) > -1000000 THEN
RETURN 1 ;
END IF;
EXCEPTION
WHEN invalid_number THEN
RETURN 0;
WHEN OTHERS THEN
RETURN 0;
END is_number;