数据库简单作业解答

数据库简单作业语句语法解答如下题：

工厂(包括厂名和厂长名)需建立一个管理数据库存储以下信息：一个工厂有多个车间，每个车间有车间号、车间主任姓名、地址和电话。一个车间有多个工人，每个工人有职工号、姓名、年龄、性别和工种。一个车间生产多种产品，产品有产品号和价格。一个车间生产多种零件，一个零件也可能为多个车间制造。一个产品由多种零件组成，一个零件也可装配出多种产品。零件有零件号、质量和价格。产品与零件均存入仓库中。厂内有多个仓库，仓库有仓库号、仓库主任姓名和电话。（相关SQL语句，创建表与增删改查，该题转自网络，解答原创）

一.时间格式一般分为3种如下

1.TIMESTAMP

显示格式：YYYY-MM-DD HH:MM:SS

时间范围:[ '1970-01-01 00:00:00'到'2037-12-31 23:59:59']

2.DATETIME

显示格式：YYYY-MM-DD HH:MM:SS

时间范围:[ '1000-01-01 00:00:00'到'9999-12-31 23:59:59']

3.DATE

显示格式：YYYY-MM-DD

时间范围：['1000-01-01'到'9999-12-31']

二.删除主外键语法

--删除外键语法：alter table 表名 drop constraint 外键约束名

--添加外键语法：alter table 表名 add constraint 外键约束名 foreign key(列名) references 引用外键表(列名)

--删除主键语法：alter table 表名 drop constraint 主键约束名

--增加主键语法：alter 表名 add constraint 主键约束名 primary key(列名)

温馨提示（删除带有外键的主键，需要先将外键删除，删除外键，得先把外键数据更新为空，然后把错误的主键的属性替换成正确的主键属性）

三.SQL语句

/*创建工厂表*/

CREATE TABLE factory(

factory_id INT PRIMARY KEY,

factory_name VARCHAR(20),

director_name VARCHAR(20)

);

/*查询成都工厂下面有哪些工人*/

SELECT a.factory_name ,b.location ,c.*FROM factory a,workshop b ,worker c WHERE a.factory_id=100 AND a.factory_id=b.factory_id AND b.workshop_id=c.workshop_id

/*查询车都车间下面要生产哪些产品*/

SELECT a.location, b.* FROM workshop a,product b, manuproduct c WHERE a.location LIKE '%成都%'AND a.workshop_id=c.workshop_id AND b.product_id=c.product_id

/*插入数据*/worker

INSERT

INTO factory(factory_id,factory_name,director_name)

VALUES ('1','神州','王洪');

INSERT

INTO factory(factory_id,factory_name,director_name)

VALUES ('2','长虹','李林');

INSERT

INTO factory(factory_id,factory_name,director_name)

VALUES ('3','长虹','刘欣');

INSERT

INTO factory(factory_id,factory_name,director_name)

VALUES ('100','华为','晓文');

INSERT

INTO factory(factory_id,factory_name,director_name)

VALUES ('101','联通','李心');

INSERT

INTO factory(factory_id,factory_name,director_name)

VALUES ('109','腾讯','刘系');

/*查询工厂编号从101-109的工厂信息*/

SELECT *FROM factory WHERE factory_id BETWEEN 101 AND 109

/*查询工厂表里面有那些姓“刘”的主任*/

SELECT *FROM factory WHERE director_name LIKE '刘%'

/*查询工厂表中第3条道第5条的数据*/

SELECT *FROM factory LIMIT 2,4

/*复制表结构及数据到新表*/

CREATE TABLE fac SELECT * FROM factory;

/*只复制表结构到新表*/

CREATE TABLE fa LIKE factory

/*删除数据要先删除外键，再删除数据，再加上外键*/

ALTER TABLE factory DROP CONSTRAINT fk_factory _name

DELETE FROM workshop WHERE workshop_id='1';

ALTER TABLE workshop ADD FOREIGN KEY(factory_name) REFERENCES factory(factory_name);

/*查表结构*/

DESC factory;

/*创建车间表*/

CREATE TABLE workshop(

workshop_id VARCHAR(20) PRIMARY KEY,

workshopdirector_name VARCHAR(20) UNIQUE,

location VARCHAR(20),

shopphone INT,

factory_id INT,

CONSTRAINT fk_factory_id FOREIGN KEY(factory_id)REFERENCES factory(factory_id)

);

/*查询车间主任的电话号码，但是电话号码后4位用X影藏*/

SELECT *FROM factory

/*插入数据*/

INSERT

INTO workshop(workshop_id,workshopdirector_name,location,shopphone,factory_id)

VALUES ('wo1','王二','墨家镇','183123456','1');

INSERT

INTO workshop(workshop_id,workshopdirector_name,location,shopphone,factory_id)

VALUES ('wo2','李三','清水镇','183123123','2');

INSERT

INTO workshop(workshop_id,workshopdirector_name,location,shopphone,factory_id)

VALUES ('wo3','刘兵','清水镇','1834323123','3');

INSERT

INTO workshop(workshop_id,workshopdirector_name,location,shopphone,factory_id)

VALUES ('wo4','杨振','成都','1834368783','1');

INSERT

INTO workshop(workshop_id,workshopdirector_name,location,shopphone,factory_id)

VALUES ('wo5','杨力','成都','1835668783','100');

INSERT

INTO workshop(workshop_id,workshopdirector_name,location,shopphone,factory_id)

VALUES ('wo5','杨力','成都','1837968783','101');

/*删除数据，删除外键*/

ALTER TABLE workshop DROP FOREIGN KEY fk_factory_name;

DELETE FROM workshop WHERE workshop_id='1';

ALTER TABLE workshop ADD FOREIGN KEY(factory_name) REFERENCES factory(factory_name);

/*修改李三为刘丽*/

UPDATE workshop SET workshopdirector_name='刘丽' WHERE workshop_id=2;

DESC workshop;

/*创建工人表*/

CREATE TABLE worker(

worker_id VARCHAR(20) PRIMARY KEY,

worker_name VARCHAR(20),

age INT,

sex CHAR,

craft VARCHAR(20),

workshop_id VARCHAR(20),

CONSTRAINT fk_workshop_id FOREIGN KEY (workshop_id)REFERENCES workshop(workshop_id)

);

/*查询名字为三个的员工信息*/

SELECT *, CHAR_LENGTH (worker_name)=3 FROM worker;

/*查询员工男女生个数*/

SELECT sex ,COUNT(*)FROM worker GROUP BY sex;

/*查询员工入职多少天*/

SELECT *, DATEDIFF(NOW(),ruzhiriqi) FROM worker

/*查询员工中男女生平均年龄*/

SELECT AVG(age) FROM worker GROUP BY sex

/*插入数据*/

INSERT