酒店预订日历预订逻辑问题

Question

I am trying to setup a hotel booking system and have run into an issue. We are trying to find where the room would be available across multiple days and months. Below are the four queries we are currently using however the admin can't book in advance until one room has NO events. Any help would be great.

$sql_statementxf1 = "Select * FROM Hotels 
  WHERE EXISTS (
    Select * FROM cal_events 
    WHERE start_date >= $end_dated 
    AND cal_events.HotelID = Hotels.HotelID 
    ORDER BY start_date) 
  AND HotelID>0 
  AND Class != 'HO' 
  ORDER BY HotelBlock, HotelNumber";
$sql_statementxf = "Select * FROM Hotels 
  WHERE EXISTS (
    Select * FROM cal_events 
    WHERE end_date >= $start_dated  
    AND cal_events.HotelID = Hotels.HotelID)  
  AND NOT EXISTS ( 
    select * from cal_events  
    WHERE start_date=$start_dated  
    AND cal_events.HotelID = Hotels.HotelID)  
  AND HotelID>0 
  AND Class != 'HO'
  ORDER BY HotelBlock, HotelNumber"; 
$sql_statementxf2 = "Select * FROM Hotels 
  WHERE NOT EXISTS ( 
    Select * FROM cal_events  
    WHERE cal_events.HotelID = Hotels.HotelID)  
  AND HotelID>0 
  AND Class != 'HO' 
  ORDER BY HotelBlock, HotelNumber";
$sql_statementxf3 = "Select * FROM Hotels 
  WHERE EXISTS ( 
    Select * FROM cal_events  
    WHERE start_date=$start_dated  
    AND end_date = $end_dated  
    AND CustomerID = $custid  
    AND PersonID != $personid  
    AND cal_events.HotelID = Hotels.HotelID)  
  AND HotelID>0 
  AND Class!='HO' 
  ORDER BY HotelBlock, HotelNumber";

Answer 1

There are a lot of mysteries in this code (like why the variable names don't seem to match up with how they are used), but one thing does stand out, $sql_statementxf2 is not like the other sections. Xf, XF1, and XF3 are all very careful about the dates. XF2 completely ignores dates, and excludes all hotels with any calendar events. That sounds like the problem behavior you are describing, since that's the only thing it does I'd say comment it and see if that gets you the results you are looking for.

To go slightly off question, It seems like what you are trying to do is find rooms without a calendar entry for the range your provide. I'm not sure how you are combining the first three statements, but they could all be replaced by using a simple or statement:

  select Hotels.* from Hotels
  where not exists 
  (
    select * from cal_events 
    where cal_events.HotelID = Hotels.HotelID
      and (cal_events.start_date between $start_Date and $End_Date
        or cal_events.end_date between $start_Date and $End_Date
        or (cal_events.start_date < $start_Date and cal_events.end_date > $End_date))
    )
      AND HotelID>0 
      AND Class != 'HO' 
  ORDER BY HotelBlock, HotelNumber

What that does is it excludes the three types of overlapping date ranges, don't show rooms where an event starts during the period, don't show rooms where events end during the period, and don't show rooms with events that start before and end after the period (a full overlap). The last one looks like you are trying to avoid a customer double booking, so that section might stay.