创建一个计算每月总收入的 PL/SQL 过程。总计必须按月打印

Question

编写一个程序，计算并显示所有酒店所有来源的总收入。总计必须按月打印，并且每个月按事件和服务类型打印。包括折扣。（如果预订日期是预订开始日期前 2 个月，则可享受 10% 的折扣）。

这些表格是：

酒店表有：

Hotel_id, hotel_name, Hotel_city, Hotel_state, Hotel_zip,Hotel_phone

预订表有：

Reservation_id, Hotel_id, Room_num, Service_id, Guest_name, Reservation_date, Reservation_start_date, Reservation_end_date, cancelation_date, Num_of_guest, event_type

房间桌子有：

Room_num, Hotel_id, Room_type, Room_capacity, Room_cost

服务表有：

service_id, Service_type, Service_cost

这是我试过的，但我想写成程序形式；我怎么做？请帮忙。谢谢

select month (Reservation_end_date) as , event_type,
sum(case when days>= 2 then cost- (cost/100)* 10
else cost) as total_cost)



((select distinct reservation.hotel_id,reservation_date, reservation_start_date,
reservation_end_date, event_type, room.room_type as R_type ,room_cost as R_cost,
months_between(reservation_start_date,reservation_date)as months
from reservation, room
where reservation.hotel_id = room.hotel_id;)

union

 (select hotel_name, reservation_date, reservation_start_date,
reservation_end_date, event_type, services_type, services_cost as cost,
months_between(reservation_start_date,reservation_date)as month
from reservation,service, hotel
where reservation.services_id = service.services_id 
and reservation.hotel_id = hotel.hotel_id;))

group by month(reservation_end_date),event_type;

Answer 1

第一步是正确获取基本查询。

要将一组日期合并到它们的常用月份中，请使用trunc(date_col, 'mm')。大概房间费用和服务费用应该按每晚计算。 要计算晚数，只需从结束日期减去开始日期即可。

此查询应该产生正确的结果（您陈述的业务规则不完整，因此很难确定）。就像您发布的代码一样，它有子查询来计算每个房间预订和每个服务预订的成本。这些在外部查询中聚合：

select to_char(r_month, 'YYYY-MON') as rpt_month
       , event_type
       , service_type
       , sum ( (r_cost - r_discount ) * no_of_nights ) as tot_cost
from (      
    select trunc(r.reservation_end_date , 'mm') as r_month
           , r.event_type
           , cast(null as varchar2(10)) as service_type
           , rm.room_cost as r_cost
           , case when months_between (r.reservation_start_date, r.reservation_date) >= 2
              then rm.room_cost * 0.1 
              else 0 end as r_discount 
            , (r.reservation_end_date - r.reservation_start_date ) as no_of_nights
    from  reservation r
          join room rm
              on ( r.room_num = rm.room_num  
              and r.hotel_id = rm.hotel_id )
    union all
    select trunc(r.reservation_end_date , 'mon') as r_month
           , r.event_type
           , sv.service_type
           , sv.service_cost  as r_cost
           , case when months_between (r.reservation_start_date, r.reservation_date) >= 2
              then sv.service_cost * 0.1 
              else 0 end as r_discount 
           , (r.reservation_end_date - r.reservation_start_date ) as no_of_nights
    from  reservation r
          join service sv
              on ( r.service_id = sv.service_id )
    )  
group by r_month
       , event_type
       , service_type
order by r_month
       , event_type
       , service_type      
;

第二步是把这个放到一个过程中。同样，您的要求是模糊的：程序是否应该采用任何参数？输出应该是什么格式？由于业务领域（酒店预订）和问题的格式（“编写一个程序...”）这似乎是一个家庭作业，所以这是对的最简单解释显示”。它使用dbms_output 例程打印到屏幕上，并使用rpad() 和lpad() 提供一个漂亮的布局（显然间距可能很不稳定，因为您没有提供各个列的数据类型）。

create or replace procedure display_monthly_reservations as
begin
    << heading >>
    dbms_output.put(rpad('MONTH', 8)); 
    dbms_output.put( rpad('EVENT_TYPE' , 20 ) || ' ');  
    dbms_output.put( rpad('SERVICE_TYPE', 20 ) || ' ');  
    dbms_output.put_line('TOTAL_COST'); 

    << per_line >>
    for r in (
         << insert the query here >> 
    ) loop
        dbms_output.put(r.rpt_month || ' '); 
        dbms_output.put( rpad(r.event_type , 20 ) || ' ');  
        dbms_output.put( rpad(r.service_type , 20 ) || ' ');  
        dbms_output.put_line( lpad(to_char(r.tot_cost , '9999999.99'), 10 ) );   
    end loop per_line;

end display_monthly_reservations;
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