我一直在尝试创建一个查询以检查两个日期之间的可用房间,但是到目前为止还没有成功。请找到用于创建下表的sql代码。我真的很需要您的帮助。这样做是因为系统要我添加更多详细信息
CREATE TABLE rooms (
id NUMERIC(3) NOT NULL,
type VARCHAR2(11) NOT NULL,
CONSTRAINT pk_rooms PRIMARY KEY (id),
CONSTRAINT fk_type
);
INSERT INTO rooms VALUES (101, 'Excellent');
INSERT INTO rooms VALUES (102, 'Excellent');
INSERT INTO rooms VALUES (103, 'Excellent');
INSERT INTO rooms VALUES (104, 'Excellent');
INSERT INTO rooms VALUES (105, 'Excellent');
INSERT INTO rooms VALUES (106, 'Excellent');
INSERT INTO rooms VALUES (107, 'Excellent');
INSERT INTO rooms VALUES (108, 'Excellent');
INSERT INTO rooms VALUES (109, 'Excellent');
INSERT INTO rooms VALUES (110, 'Excellent');
INSERT INTO rooms VALUES (111, 'Excellent');
INSERT INTO rooms VALUES (112, 'Excellent');
CREATE TABLE bookings_roombookings (
book_id VARCHAR(20) NOT NULL,
room_id NUMBER NOT NULL,
fromdate DATE NOT NULL,
todate DATE NOT NULL,
guest1 VARCHAR(40) NOT NULL,
guest2 VARCHAR(40),
guest3 VARCHAR(40),
CONSTRAINT cpk PRIMARY KEY (book_id, room_id),
CONSTRAINT fk_rid FOREIGN KEY (room_id) REFERENCES rooms(id));
INSERT INTO bookings_roombookings VALUES (
'DTR5000000', 320,
'01-JUN-2020', '01-SEP-2020',
'D.Trump', 'H.Clinton', 'S.Daniels');
INSERT INTO bookings_roombookings VALUES (
'DRI0000002', 102,
'11-DEC-19', '01-SEP-20',
'D.Ridley', NULL, NULL);
我的查询如下:
select r.id from rooms r
where r.id not in
( select bkr.room_id from bookings_roombookings bkr
where (fromdate > '15-JUN-20') and (todate < '18-JUN-20') );
但是这将返回bkr表的两行。我将不胜感激。
答案 0 :(得分:1)
您可以从room
表开始,并在相关子查询中使用not exists
条件,以消除预订时间与目标日期范围重叠的房间:
select r.*
from rooms r
where not exists (
select 1
from bookings_roombookings bkr
where
bkr.room_id = r.id
and bkr.fromdate <= date'2020-06-15'
and bkr.todate >= date'2020-06-18'
)
注意:不要依赖于从字符串到日期的隐式转换(如fromdate > '15-JUN-20'
),这取决于数据库和会话的nls设置;相反,您可以使用日期文本,它们是ANSI SQL标准的一部分,并且受Oracle支持,例如date'yyyy-mm-dd'
。