Problem with calculate difference between two dates on monday to saturday

Question

Hello,
I need some help to edit a function tu return number of hours between to dates, including saturdays (09:00 - 14:00) and monday to friday (09:00-21:00);
This is my code;
CREATE OR REPLACE
FUNCTION TEST2( FECHA_INICIO DATE, FECHA_FIN DATE)
    RETURN NUMBER IS HORASTOTALES NUMBER;
    fecha date;
    BEGIN
    if(
      SELECT fecha, to_char(fecha, 'DY', 'NLS_DATE_LANGUAGE=ENGLISH') Dia
    FROM (SELECT to_date('FECHA_INICIO') + LEVEL - 1 fecha
           FROM DUAL
        CONNECT BY LEVEL <= (FECHA_FIN - FECHA_INICIO))
  WHERE TO_CHAR(FECHA, 'DY', 'NLS_DATE_LANGUAGE=ENGLISH') not IN ('SAT') THEN
        with t as (
        SELECT  CASE LEVEL
                             when 1 then greatest(fecha_inicio,trunc(fecha_inicio) + 9 / 24)
                             else trunc(fecha_inicio) + level - 15 / 24
                           end fecha_inicio,
                           case connect_by_isleaf
                             when 1 then least(fecha_fin,trunc(fecha_fin) + 21 / 24)
                             else trunc(fecha_inicio) + level - 3 / 24
                           end fecha_fin
                     from  dual
                     connect by level <= trunc(fecha_fin) - trunc(fecha_inicio) + 1 )
        select  sum(greatest(fecha_fin - fecha_inicio,0)) * 24 horas
          into  horastotales
          FROM  T
                   WHERE TRUNC(FECHA_INICIO) - TRUNC(FECHA_INICIO,'iw') < 5 ;
        RETURN HORASTOTALES ;
        ) ELSE IF
        return HORASTOTALES+5;
END;
regards

Answer 1

Ok, let's try this one then. it works as a function, and if you extract the query, it can work as a single cursor too.
create or replace function test2( p_start_date date, p_end_date date) return number
is
   t_result number;
begin
   with firstday as ( select case to_char(p_start_date,'fmdy','NLS_DATE_LANGUAGE=ENGLISH')
                            when 'sun' then 0
                            when 'sat' then 9-least(14,to_char(p_start_date,'hh24'))
                            else 9-least(21,to_char(p_start_date,'hh24'))
                         end day
                    from dual ),
        alldays  as (select sum(case to_number(to_char(p_start_date+level-1,'d'))
                                   when 1 then 0
                                   when 7 then 5
                                   else 12
                                end) days
                       from dual
                     connect by level <= p_end_date - p_start_date + 1),  
         lastday as ( select case to_char(p_end_date,'fmdy','NLS_DATE_LANGUAGE=ENGLISH')
                            when 'sun' then 0
                            when 'sat' then -14+least(14,to_char(p_end_date,'hh24'))
                            else -21+least(21,to_char(p_end_date,'hh24'))
                         end day
                    from dual )
   select sum(t1.day+t2.days+t3.day)
     into t_result
     from firstday t1
        , alldays  t2
        , lastday  t3;
   return t_result;
end;