Question

我有以下表结构：

roominfo表

+---------+----------------+---------------+
| Room_id | room_type_name | maximum_rooms |
+---------+----------------+---------------+
|       1 | A              |            16 |
|       2 | B              |            14 |
|       3 | C              |             7 |
|       4 | D              |             2 |
|       5 | E              |             2 |
+---------+----------------+---------------+

bookedtable存储该日期内预订的所有客房：

+------------+--------------+---------------+----------------+---------+
| room_bk_id | checkin_date | checkout_date | maxroomsbooked | room_id |
+------------+--------------+---------------+----------------+---------+
|          1 | 2014-01-28   | 2014-01-29    |              8 |       1 |
|          2 | 2014-01-29   | 2014-01-30    |              2 |       4 |
|          3 | 2014-01-28   | 2014-01-29    |              4 |       1 |
+------------+--------------+---------------+----------------+---------+

bookingprogress表以避免竞争条件（它阻止到期时间）我将最长到期时间设置为距离当前时间15分钟

+------------+----------------+-----------------+----------------+---------+---------------+---------------------+
| room_pg_id | checkinpg_date | checkoutpg_date | maxroomsbooked | room_id |   sessionid   |     ExpireTime      |
+------------+----------------+-----------------+----------------+---------+---------------+---------------------+
|          1 | 2014-01-28     | 2014-01-29      |              2 |       1 | AdsddsA23asd  | 2014-01-28 00:15:00 |
|          2 | 2014-01-29     | 2014-01-30      |              2 |       5 | AdsQWerasdwe  | 2014-01-28 00:18:00 |
|          3 | 2014-01-28     | 2014-01-29      |              1 |       2 | BdrtQWerasdwe | 2014-01-28 00:20:00 |
+------------+----------------+-----------------+----------------+---------+---------------+---------------------+

工作流程为：

用户通过提供入住日期，结帐日期和房间号来检查可用房间。
我需要查找并显示在特定时间段内未被阻止或预订的房间。

执行的查询是（可能是小错误 - 在这里我概述了我所做的事情 - 根据这个修改我的查询）

SELECT   tbook.*,
         SUM(tbook.maxroomsbooked + tprogress.maxroomsbooked) AS bookedrooms
FROM     bookedtable     AS tbook
    JOIN bookingprogress AS tprogress USING (Room_id)
    JOIN roominfo        AS troomtype USING (Room_id)
WHERE    tbook.checkout_date       > '2014-01-28'
     AND tprogress.checkoutpg_date > '2014-01-28'
     AND tprogress.ExpireTime      < '2014-01-27 00:10:00'
     AND tprogress.room_id         = 1
GROUP BY Room_id

从上表中我试图获得可预订的房间。但我没有得到预期的结果。

在sqlfiddle上查看。

你能帮我解决一下吗？

Answer 1

一种方法是使用NOT EXISTS subqueries。例如，如果用户有兴趣预订'2014-02-01'至'2014-02-07'：

SELECT * 
FROM   roominfo r
WHERE  NOT EXISTS (
         SELECT *
         FROM   bookedtable b
         WHERE  b.room_id = r.room_id
            AND NOT (
                  b.checkin_date  < '2014-02-07'
              AND b.checkout_date > '2014-02-01'
                )
         LIMIT  1
       )
   AND NOT EXISTS (
         SELECT *
         FROM   bookingprogress p
         WHERE  p.room_id = r.room_id
            AND p.ExpireTime > CURRENT_TIME
            AND NOT (
                  p.checkinpg_date  < '2014-02-07'
              AND p.checkoutpg_date > '2014-02-01'
                )
         LIMIT  1
       )

从下表结构中找到可用房间的数量

1 个答案: