新建产品库mydb6_product，新建4张表如下:
#新建库
mysql> create database mydb6_product;
Query OK, 1 row affected (0.00 sec)
employees表
列1:id，整型，主键
列2:name，字符串，最大长度50，不能为空
列3:age，整型
列4:gender，字符串，最大长度10，不能为空，默认值“unknown”.
列5:salary，浮点型
#使用mydb6_product数据库
mysql> use mydb6_product;
#创建employees表
mysql> create table employees (
-> id int primary key,
-> name varchar(50) not null,
-> age int,
-> gender varchar(10) not null default "unknown",
-> salary float);
orders表
列1:id，整型，主键
列2:name，字符串，最大长度100，不能为空
列3:price，浮点型
列4:quantity，整型
列5:category，字符串，最大长度50
mysql> create table orders (
-> id int primary key,
-> name varchar(100) not null,
-> price float,
-> quantity int,
-> category varchar(50));
Query OK, 0 rows affected (0.00 sec)
involces表
列1:number，整型，主键自增长
列2:order_id，整型，外键关联到orders表的id列
列3:in_date: 日期型
列4:totalamount:浮点型，要求数据大于0
mysql> create table involces (
-> number int primary key auto_increment,
-> order_id int, constraint fk_order foreign key (order_id) references orders(id),
-> in_date date,
-> totalamount float, check(totalamount > 0));
新建工人库
mysgl>create database mydb8 worker:
mysql> create database mydb8_worker;
Query OK, 1 row affected (0.00 sec)
使用工人库
mysql> use mydb8_worker;
mysql> use mydb8_worker;
Database changed
创建worker表
mysql> create table t worker(
department id int(11)not null comment部门号’，
worker_id int(11)primary key not nu1l comment’职工号’，
worker_date date not null comment’作时间’，
wages float(8,2)not null comment’工资’
politics varchar(10)not nu1l default’群众’ comment’政治面貌’,，
name varchar(20)not nullcomment’姓名’，
borth date date not null comment’出生日期’);
mysql> create table t_worker(
-> department_id int(11) not null comment '部门号',
-> worker_id int(11) primary key not null comment '职工号',
-> worker_data date not null comment '工作时间',
-> wages float(8,2) not null comment '工资',
-> politics varchar(10) not null default '群众' comment '政治面貌',
-> name varchar(20) not null comment '姓名',
-> borth_date date not null comment '出生日期');
Query OK, 0 rows affected, 3 warnings (0.03 sec)
#查一下
mysql> desc t_worker;
+---------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------+-------------+------+-----+---------+-------+
| department_id | int | NO | | NULL | |
| worker_id | int | NO | PRI | NULL | |
| worker_data | date | NO | | NULL | |
| wages | float(8,2) | NO | | NULL | |
| politics | varchar(10) | NO | | 群众 | |
| name | varchar(20) | NO | | NULL | |
| borth_date | date | NO | | NULL | |
+---------------+-------------+------+-----+---------+-------+
7 rows in set (0.00 sec)
插入数据
insert into t worker values(101,1001,‘2015-5-4’,7500.00,‘群众’,‘张春燕’‘1990-7-1’);
mysql> insert into t_worker values (101,1001,'2015-5-4',7500.00,'群众','张春燕','1990-7-1');
Query OK, 1 row affected (0.01 sec)
insert into t worker values(101,1002,‘2019-2-6’,5200.00.'团员’,‘李名博’‘1997-2–8’):
mysql> insert into t_worker values (101,1002,'2019-2-6',5200.00,'团员','李明博','1997-2-8');
Query OK, 1 row affected (0.00 sec)
insert into t_worker values(102,1003,‘2008-1-4’,10500.00,‘党员’,‘王博涵’,‘1983-6-8’);
mysql> insert into t_worker values (102,1003,'2008-1-4',10500.00,'党员','王博涵','1983-6-8');
Query OK, 1 row affected (0.00 sec)
insert into t_worker values (102,1004,‘2016-10-10’,5500.00,‘群众’,‘赵小军’,‘1994-9-5’);
insert into t_worker values (102,1004,'2016-10-10',5500.00,'群众','赵小军','1994-9-5');
Query OK, 1 row affected (0.02 sec)
insert into tworker values(102,1005，‘2014-4-1’,8800.00，‘党员’，‘钱有财’,‘1992-12-30’);
insert into t_worker values (102,1005,'2014-4-1',8800.00,'党员','钱有才','1992-12-30');
Query OK, 1 row affected (0.00 sec)
insert into t_worker values(103,1006,‘2019-5-5’,5500.00,‘党员’,'孙菲菲’,‘1996-9-2’);
mysql> insert into t_worker values (103,1006,'2019-5-5',5500.00,'党员','孙菲菲','1996-9-2');
Query OK, 1 row affected (0.00 sec)
完成查询
显示所有职工的基本信息。
mysql> select * from t_worker;
+---------------+-----------+-------------+----------+----------+-----------+------------+
| department_id | worker_id | worker_data | wages | politics | name | borth_date |
+---------------+-----------+-------------+----------+----------+-----------+------------+
| 101 | 1001 | 2015-05-04 | 7500.00 | 群众 | 张春燕 | 1990-07-01 |
| 101 | 1002 | 2019-02-06 | 5200.00 | 团员 | 李明博 | 1997-02-08 |
| 102 | 1003 | 2008-01-04 | 10500.00 | 党员 | 王博涵 | 1983-06-08 |
| 102 | 1004 | 2016-10-10 | 5500.00 | 群众 | 赵小军 | 1994-09-05 |
| 102 | 1005 | 2014-04-01 | 8800.00 | 党员 | 钱有才 | 1992-12-30 |
| 103 | 1006 | 2019-05-05 | 5500.00 | 党员 | 孙菲菲 | 1996-09-02 |
+---------------+-----------+-------------+----------+----------+-----------+------------+
6 rows in set (0.00 sec)
查询所有职工所属部门的部门号，不显示重复的部门号。
mysql> select distinct department_id from t_worker;
+---------------+
| department_id |
+---------------+
| 101 |
| 102 |
| 103 |
+---------------+
3 rows in set (0.02 sec)
求出所有职工的人数。
mysql> select count(1) from t_worker;
+----------+
| count(1) |
+----------+
| 6 |
+----------+
1 row in set (0.00 sec)
列出最高工和最低工资。
mysql> select min(wages),max(wages) from t_worker;
+------------+------------+
| min(wages) | max(wages) |
+------------+------------+
| 5200.00 | 10500.00 |
+------------+------------+
1 row in set (0.00 sec)
列出职工的平均工资和总工资。
mysql> select avg(wages),sum(wages) from t_worker;
+-------------+------------+
| avg(wages) | sum(wages) |
+-------------+------------+
| 7166.666667 | 43000.00 |
+-------------+------------+
1 row in set (0.00 sec)
创建一个只有职工号、姓名和参加工作的新表，名为工作日期表。
mysql> create table work_date (
-> worker_id int primary key,
-> name varchar(50),
-> is_work char(5) not null);
Query OK, 0 rows affected (0.01 sec)
mysql> desc work_date;
+-----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| worker_id | int | NO | PRI | NULL | |
| name | varchar(50) | YES | | NULL | |
| is_work | char(5) | NO | | NULL | |
+-----------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
显示所有党员的年龄。
mysql> select name,borth_date, timestampdiff(year,borth_date,curdate()) as age from t_worker where politics='党员';
+-----------+------------+------+
| name | borth_date | age |
+-----------+------------+------+
| 王博涵 | 1983-06-08 | 42 |
| 钱有才 | 1992-12-30 | 32 |
| 孙菲菲 | 1996-09-02 | 28 |
+-----------+------------+------+
3 rows in set (0.00 sec)
列出工资在4000-8000之间的所有职工姓名，
mysql> select name from t_worker where wages between 4000 and 8000;
+-----------+
| name |
+-----------+
| 张春燕 |
| 李明博 |
| 赵小军 |
| 孙菲菲 |
+-----------+
4 rows in set (0.00 sec)
列出所有孙4姓和李姓的职工姓名。
mysql> select name from t_worker where name regexp '^[孙李]';
+-----------+
| name |
+-----------+
| 李明博 |
| 孙菲菲 |
+-----------+
2 rows in set (0.03 sec)
列出所有部门号为102和103日不是党员的职工号、姓名。
mysql> select department_id,name from t_worker where politics !='党员' and department_id in (102,
,103);
+---------------+-----------+
| department_id | name |
+---------------+-----------+
| 102 | 赵小军 |
+---------------+-----------+
1 row in set (0.00 sec)
将职工表t_worker中的职工按出生的先后顺序排序。
mysql> select name,worker_data from t_worker order by worker_data asc;
+-----------+-------------+
| name | worker_data |
+-----------+-------------+
| 王博涵 | 2008-01-04 |
| 钱有才 | 2014-04-01 |
| 张春燕 | 2015-05-04 |
| 赵小军 | 2016-10-10 |
| 李明博 | 2019-02-06 |
| 孙菲菲 | 2019-05-05 |
+-----------+-------------+
6 rows in set (0.00 sec)
显示工资最高的前3名职工的职工号和姓名。
mysql> select worker_id,name from t_worker order by wages desc limit 0,3;
+-----------+-----------+
| worker_id | name |
+-----------+-----------+
| 1003 | 王博涵 |
| 1005 | 钱有才 |
| 1001 | 张春燕 |
+-----------+-----------+
3 rows in set (0.00 sec)
求出各部门党员的人数。
ysql> select department_id,count(*) from t_worker where politics='党员' group by department_id;
+---------------+----------+
| department_id | count(*) |
+---------------+----------+
| 102 | 2 |
| 103 | 1 |
+---------------+----------+
2 rows in set (0.00 sec)
统计各部门的工资和平均工资并保留2位小数
mysql> select department_id,sum(wages) '工资总和',format(avg(wages),2) '平均工资' from t_worker group by departtment_id;
+---------------+--------------+--------------+
| department_id | 工资总和 | 平均工资 |
+---------------+--------------+--------------+
| 101 | 12700.00 | 6,350.00 |
| 102 | 24800.00 | 8,266.67 |
| 103 | 5500.00 | 5,500.00 |
+---------------+--------------+--------------+
3 rows in set (0.00 sec)
列出总人数大于等于3的部门号和总人数。
mysql> select department_id,count(1) from t_worker group by department_id having count(1)>=3;
+---------------+----------+
| department_id | count(1) |
+---------------+----------+
| 102 | 3 |
+---------------+----------+
1 row in set (0.00 sec)