ORACLE判断日期、时间的字符串是否有效日期、时间

 /* ===============================================================================================
    Function Name:IS_DATE      
    Description: 判斷輸入的日期和指定格式 是否為有效日期, 返回:數值類型, 1:是, 0:否; 空值:返回0. 
    Argument: p_date_str         IN   DATE_string    日期的字符串, 如:"2021/07/09"
              p_format           IN   日期格式, 如: YYYY/MM/DD         
    History: 
      1.00  2021/7/09  samrv  Creation
  *================================================================================================*/
  function is_date(p_date_str varchar2, p_format varchar2) return number is
    v_format varchar2(20);
    v_date date;
    v_result number;
  begin
    v_result :=0;
     
     --v_format := nvl(p_format,'yyyy-mm-dd');
    
     
    begin    
     v_date := to_date(nvl(p_date_str, 'a') , p_format);
        v_result := 1;
    exception
    when others then
        return 0;
    end;
    
    return v_result; 
       
  end;
  
  /* ===============================================================================================
    Function Name:IS_TIME      
    Description: 判斷輸入的時間和指定格式 是否為有效時間, 返回:數值類型, 1:是, 0:否; 空值:返回0. 
    Argument: p_time_str         IN   time_string    日期的字符串, 如:"200749" 表示: 20:07:49
              p_format           IN   日期格式, 如:HH24MISS 表示24小時制 HH24:MI:SS 或 12小時制 HH:MI:SS           
    History: 
      1.00  2021/7/09  samrv  Creation
  *================================================================================================*/    
   FUNCTION IS_TIME(P_TIME_STR IN VARCHAR2,p_format varchar2) RETURN NUMBER is
     v_time NUMBER;
     v_hh varchar2(4);
     v_mi varchar2(2);
     v_ss varchar2(2); 
     V_RESULT NUMBER;
   begin
     V_RESULT := 0 ;
     
    BEGIN
      v_TIME := TO_NUMBER(nvl(P_TIME_STR, 'a') );
       -- V_RESULT := 1;
    
         
     if p_format= 'HH24MI' THEN
       SELECT SUBSTR(P_TIME_STR,1,2) ,SUBSTR(P_TIME_STR,3,2)
         INTO V_HH,V_MI
        FROM DUAL;
     
       IF TO_NUMBER(V_HH)>=0 AND TO_NUMBER(V_HH)<24 AND TO_NUMBER(V_MI)>=0 AND TO_NUMBER(V_MI)<=59 THEN
          V_RESULT := 1;
       ELSE 
          V_RESULT :=0;
       END IF;
          
      -- END IF;
     
     ELSif p_format= 'HH24MISS' THEN
       SELECT SUBSTR(P_TIME_STR,1,2) ,SUBSTR(P_TIME_STR,3,2),SUBSTR(P_TIME_STR,5,2)
         INTO V_HH,V_MI, V_SS
        FROM DUAL;
     
       IF TO_NUMBER(V_HH)>=0 AND TO_NUMBER(V_HH)<24 AND TO_NUMBER(V_MI)>=0 AND TO_NUMBER(V_MI)<=59 AND  TO_NUMBER(V_SS)>=0 AND TO_NUMBER(V_SS)<=59 THEN
          V_RESULT := 1;
       ELSE 
          V_RESULT :=0;
       END IF;
          
      -- END IF;
     
     ELSif p_format= 'HHMI' THEN
       SELECT SUBSTR(P_TIME_STR,1,2) ,SUBSTR(P_TIME_STR,3,2)
         INTO V_HH,V_MI
        FROM DUAL;
     
       IF TO_NUMBER(V_HH)>=0 AND TO_NUMBER(V_HH)<=12 AND TO_NUMBER(V_MI)>=0 AND TO_NUMBER(V_MI)<=59 THEN
          V_RESULT := 1;
       ELSE 
          V_RESULT :=0;
       END IF;
          
     --END IF;
     
     ELSif p_format= 'HHMISS' THEN
       SELECT SUBSTR(P_TIME_STR,1,2) ,SUBSTR(P_TIME_STR,3,2),SUBSTR(P_TIME_STR,5,2)
         INTO V_HH,V_MI, V_SS
        FROM DUAL;
     
       IF TO_NUMBER(V_HH)>=0 AND TO_NUMBER(V_HH)<=12 AND TO_NUMBER(V_MI)>=0 AND TO_NUMBER(V_MI)<=59 AND  TO_NUMBER(V_SS)>=0 AND TO_NUMBER(V_SS)<=59 THEN
          V_RESULT := 1;
       ELSE 
          V_RESULT :=0;
       END IF;
          
     END IF;
     
     exception
     when others then
       return 0;
     END;
       
     RETURN V_RESULT;
     
   end;  
  
 /* ===============================================================================================
    Function Name:IS_numeric       
    Description: 判斷輸入數值的字符串是否為有效數值(十進制), 返回:數值類型, 1:是, 0:否; 空值:返回0. 
    Argument: p_str         IN   DATE_string    日期的字符串, 如:"20107.09"  
    History: 
      1.00  2021/7/09  samrv  Creation
  *================================================================================================*/  
   FUNCTION is_numeric (p_str IN VARCHAR2)
    RETURN NUMBER
IS
    v_str FLOAT;
BEGIN
    IF p_str IS NULL
    THEN
       RETURN 0;
    ELSE
       BEGIN
          SELECT TO_NUMBER (p_str)
            INTO v_str
            FROM DUAL;
       EXCEPTION
          WHEN INVALID_NUMBER
          THEN
             RETURN 0;
       END;

       RETURN 1;
    END IF;
END is_numeric;