对于MySQL中视图的相关实验

以下用该表举例：

/*Table structure for table `employees` */

DROP TABLE IF EXISTS `employees`;

CREATE TABLE `employees` (
`employee_id` int(6) NOT NULL DEFAULT '0',
`first_name` varchar(20) DEFAULT NULL,
`last_name` varchar(25) NOT NULL,
`email` varchar(25) NOT NULL,
`phone_number` varchar(20) DEFAULT NULL,
`hire_date` date NOT NULL,
`job_id` varchar(10) NOT NULL,
`salary` double(8,2) DEFAULT NULL,
`commission_pct` double(2,2) DEFAULT NULL,
`manager_id` int(6) DEFAULT NULL,
`department_id` int(4) DEFAULT NULL,
PRIMARY KEY (`employee_id`),
UNIQUE KEY `emp_email_uk` (`email`),
UNIQUE KEY `emp_emp_id_pk` (`employee_id`),
KEY `emp_dept_fk` (`department_id`),
KEY `emp_job_fk` (`job_id`),
KEY `emp_manager_fk` (`manager_id`),
CONSTRAINT `emp_manager_fk` FOREIGN KEY (`manager_id`) REFERENCES `employees` (`employee_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

/*Data for the table `employees` */

insert into `employees`(`employee_id`,`first_name`,`last_name`,`email`,`phone_number`,`hire_date`,`job_id`,`salary`,`commission_pct`,`manager_id`,`department_id`)
values (100,'Steven','King','SKING','515.123.4567','1987-06-17','AD_PRES',24000.00,NULL,NULL,90),
(101,'Neena','Kochhar','NKOCHHAR','515.123.4568','1989-09-21','AD_VP',17000.00,NULL,100,90),
(102,'Lex','De Haan','LDEHAAN','515.123.4569','1993-01-13','AD_VP',17000.00,NULL,100,90),
(103,'Alexander','Hunold','AHUNOLD','590.423.4567','1990-01-03','IT_PROG',9000.00,NULL,102,60),
(104,'Bruce','Ernst','BERNST','590.423.4568','1991-05-21','IT_PROG',6000.00,NULL,103,60),
(105,'David','Austin','DAUSTIN','590.423.4569','1997-06-25','IT_PROG',4800.00,NULL,103,60),
(106,'Valli','Pataballa','VPATABAL','590.423.4560','1998-02-05','IT_PROG',4800.00,NULL,103,60),
(107,'Diana','Lorentz','DLORENTZ','590.423.5567','1999-02-
(132,'TJ','Olson','TJOLSON','650.124.8234','1999-04-10','ST_CLERK',2100.00,NULL,121,50),
(133,'Jason','Mallin','JMALLIN','650.127.1934','1996-06-14','ST_CLERK',3300.00,NULL,122,50),
(134,'Michael','Rogers','MROGERS','650.127.1834','1998-08-26','ST_CLERK',2900.00,NULL,122,50),
(135,'Ki','Gee','KGEE','650.127.1734','1999-12-12','ST_CLERK',2400.00,NULL,122,50),
(136,'Hazel','Philtanker','HPHILTAN','650.127.1634','2000-02-06','ST_CLERK',2200.00,NULL,122,50),
(165,'David','Lee','DLEE','011.44.1346.529268','2000-02-23','SA_REP',6800.00,0.10,147,80),
(166,'Sundar','Ande','SANDE','011.44.1346.629268','2000-03-24','SA_REP',6400.00,0.10,147,80),
(167,'Amit','Banda','ABANDA','011.44.1346.729268','2000-04-21','SA_REP',6200.00,0.10,147,80),
(168,'Lisa','Ozer','LOZER','011.44.1343.929268','1997-03-11','SA_REP',11500.00,0.25,148,80),
(181,'Jean','Fleaur','JFLEAUR','650.507.9877','1998-02-23','SH_CLERK',3100.00,NULL,120,50),
(182,'Martha','Sullivan','MSULLIVA','650.507.9878','1999-06-21','SH_CLERK',2500.00,NULL,120,50),
(183,'Girard','Geoni','GGEONI','650.507.9879','2000-02-03','SH_CLERK',2800.00,NULL,120,50),
(184,'Nandita','Sarchand','NSARCHAN','650.509.1876','1996-01-27','SH_CLERK',4200.00,NULL,121,50),
(185,'Alexis','Bull','ABULL','650.509.2876','1997-02-20','SH_CLERK',4100.00,NULL,121,50),
(186,'Julia','Dellinger','JDELLING','650.509.3876','1998-06-24','SH_CLERK',3400.00,NULL,121,50),
(187,'Anthony','Cabrio','ACABRIO','650.509.4876','1999-02-07','SH_CLERK',3000.00,NULL,121,50),
(188,'Kelly','Chung','KCHUNG','650.505.1876','1997-06-14','SH_CLERK',3800.00,NULL,122,50),
(189,'Jennifer','Dilly','JDILLY','650.505.2876','1997-08-13','SH_CLERK',3600.00,NULL,122,50),
(190,'Timothy','Gates','TGATES','650.505.3876','1998-07-11','SH_CLERK',2900.00,NULL,122,50),
(191,'Randall','Perkins','RPERKINS','650.505.4876','1999-12-19','SH_CLERK',2500.00,NULL,122,50),
(206,'William','Gietz','WGIETZ','515.123.8181','1994-06-07','AC_ACCOUNT',8300.00,NULL,205,110);