oracle 判斷是否是數字

參數是數字則返回1，不是數字則返回0.

CREATE FUNCTION F_IS_NUM(P_NUM IN VARCHAR2) RETURN NUMBER AS
V_TMP NUMBER;
BEGIN
IF P_NUM IS NULL THEN
RETURN NULL;
END IF;
V_TMP := TO_NUMBER(P_NUM);
RETURN 1;
EXCEPTION
WHEN OTHERS THEN
RETURN 0;
END F_IS_NUM;