4．实验方法和步骤（含设计）
CREATE TABLE `hotel_room` (
`room_num` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
`type` varchar(32) DEFAULT NULL,
`price` double DEFAULT NULL,
`status` varchar(32) DEFAULT NULL,
PRIMARY KEY (`room_num`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into `hotel_room`(`room_num`,`type`,`price`,`status`) values
('101','普通标间',199,'空'),
('102','普通标间',199,'住'),
('103','普通标间',199,'脏'),
('104','普通标间',199,'空'),
('201','标准双人',229,'空'),
('202','标准双人',229,'空'),
('301','商务大床',229,'空'),
('302','商务大床',229,'空'),
('401','商务双床',299,'空'),
('402','商务双床',299,'空'),
('501','商务双床',269,'空'),
('502','商务双床',269,'空');
CREATE TABLE `hotel_record` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`room_num` varchar(32) DEFAULT NULL,
`room_type` varchar(32) DEFAULT NULL,
`price` double DEFAULT NULL,
`checkin_date` datetime DEFAULT NULL,
`leave_date` datetime DEFAULT NULL,
`status` varchar(32) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
insert into
`hotel_record`(`id`,`room_num`,`room_type`,`price`,`checkin_date`,`leave_date`,`sta
tus`) values
(1,'101','普通标间',1791,'2023-12-04 14:01:23','2023-12-13 09:01:24','已结账'),
(2,'102','普通标间',3980,'2023-11-23 23:33:12','2023-12-13 09:02:32','已结账'),
(3,'103','普通标间',199,'2023-12-04 23:33:12','2023-12-04 11:00:00','已结账'),
(4,'101','普通标间',199,'2023-12-13 09:25:41','2023-12-13 09:26:34','已结账'),
(5,'102','普通标间',199,'2023-12-13 09:27:47','2023-12-14 12:00:00','入住中');
CREATE TABLE `hotel_customer` (
`id` varchar(32) NOT NULL,
`name` varchar(16) DEFAULT NULL,
`gender` varchar(16) DEFAULT NULL,
