CREATE OR REPLACE FUNCTION get_num_hour(
    data_in DATE)
  RETURN NUMBER
IS
  CURSOR big_data
  IS
    SELECT DISTINCT
      CASE
        WHEN to_date (TO_CHAR ( MAX(data_in) OVER (PARTITION BY TRUNC(data_in,
          'DD'), SUBSTR(who_is, 1, instr(Who_is, '.')) ), 'HH24:MI:SS'),
          'HH24:MI:SS') <= to_date ('17:46:00', 'HH24:MI:SS')
        THEN 0
        ELSE to_number(floor((((to_number( to_date(TO_CHAR(MAX(data_in)OVER(
          PARTITION BY TRUNC(data_in, 'DD'),SUBSTR(who_is, 1, instr(Who_is, '.'
          )) ), 'HH24:MI:SS'), 'HH24:MI:SS') - to_date ('17:30:00',
          'HH24:MI:SS'))                     *1440 ))/ 60)) )
      END hours,
      CASE
        WHEN to_date (TO_CHAR ( MAX(data_in) OVER (PARTITION BY TRUNC(data_in,
          'DD'), SUBSTR(who_is, 1, instr(Who_is, '.')) ), 'HH24:MI:SS'),
          'HH24:MI:SS') <= to_date ('17:46:00', 'HH24:MI:SS')
        THEN 0
        ELSE to_number(EXTRACT(MINUTE FROM NUMTODSINTERVAL((to_date (TO_CHAR (
          MAX(data_in) OVER (PARTITION BY TRUNC(data_in, 'DD'), SUBSTR(who_is,
          1, instr(Who_is, '.')) ), 'HH24:MI:SS'), 'HH24:MI:SS') - to_date (
          '17:30:00', 'HH24:MI:SS') )                            *1440,'MINUTE'
          )))
      END minutes
    FROM
      pr_t_g
    WHERE
      TRUNC (data_in, 'DD') NOT IN ( to_date ('04.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('05.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('11.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('12.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('18.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('19.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('25.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss'), to_date ('26.02.2017 00:00:00',
      'dd.mm.yyyy hh24:mi:ss') ) ;
TYPE hourstab IS   TABLE OF big_data%rowtype;
  v_hoursandminutes hourstab;
  cnumber NUMBER;
BEGIN
  OPEN big_data;
  FETCH
    big_data bulk collect
  INTO
    v_hoursandminutes;
  CLOSE big_data;
  FOR i IN v_hoursandminutes.first..v_hoursandminutes.last
  LOOP
    IF v_hoursandminutes(i).minutes < 15
      THEN
      cnumber := to_number (v_hoursandminutes(i).hours);
      /*elsif v_hoursandminutes(i).minutes >= 45
      then cnumber := v_hoursandminutes(i).hours + 1;
      elsif v_hoursandminutes(i).minutes >= 16
      then cnumber := v_hoursandminutes(i).hours + 0.5;*/
    ELSE
      NULL;
    END IF;
  END LOOP;
  RETURN cnumber;
EXCEPTION
WHEN OTHERS THEN
  raise_application_error(-20001,'An error was encountered - ##'||SQLCODE||
  '## -ERROR- ##'||SQLERRM);
END;

 ORA-20001: An error was encountered - ##-6502## -ERROR- ##ORA-06502: PL/SQL: numeric or value error

 FOR i IN v_hoursandminutes.first..v_hoursandminutes.last

ORA-06502: PL/SQL: numeric or value error
ORA-06512: at "M.GET_NUM_HOUR", line 50
06502. 00000 -  "PL/SQL: numeric or value error%s"
*Cause:    An arithmetic, numeric, string, conversion, or constraint error
           occurred. For example, this error occurs if an attempt is made to
           assign the value NULL to a variable declared NOT NULL, or if an
           attempt is made to assign an integer larger than 99 to a variable
           declared NUMBER(2).
*Action:   Change the data, how it is manipulated, or how it is declared so
           that values do not violate constraints.

to_date ('04.02.2017 00:00:00', 'dd.mm.yyyy hh24:mi:ss')

bulk collect
  FOR i IN v_hoursandminutes.first..v_hoursandminutes.last

FOR i IN 1..v_hoursandminutes.count