php - 我怎样才能简化这个关于预订的查询？

Question

我有酒店预订系统，当用户输入一个新的预订日期和期间我需要检索所有未预订的房间，

reservations 表包含 room_id, startdate, period

我写了这个查询，只是需要简化它

select * 
from rooms 
where id in (
   select room_id 
   from reservations 
   where '2018-6-11' not BETWEEN date_at and date_add(date_at, INTERVAL period day) 
   and '2018-6-30' not between date_at and date_add(date_at, INTERVAL period day) 
   and date_at not between '2018-6-11' and '2018-6-30' 
   and date_add(date_at ,INTERVAL period day ) not between '2018-6-11' and '2018-6-30' ) 
or id not in (select room_id from reservations)

Answer 1

如何将 IN 子句转换为等效连接？请参阅以下查询是否适用于您的情况:

SELECT *
FROM rooms rm
JOIN 
   (SELECT room_id rmid
  FROM reservations
  WHERE '2018-6-11' NOT BETWEEN date_at AND date_add(date_at, INTERVAL period DAY)
  AND '2018-6-30' NOT BETWEEN date_at AND date_add(date_at, INTERVAL period DAY)
  AND date_at NOT BETWEEN '2018-6-11' AND '2018-6-30'
  AND date_add(date_at ,INTERVAL period DAY ) NOT BETWEEN '2018-6-11' AND '2018-6-30'
  ) tb1  
ON  rm.ID = tb.rmid 
JOIN reservations rv
ON rm.ID <> rv.room_id;