MySQL
DROP TABLE IF EXISTS emp01;
DROP TABLE IF EXISTS emp02;
DROP TABLE IF EXISTS emp03;
DROP TABLE IF EXISTS emp11;
DROP TABLE IF EXISTS dept02;
DROP TABLE IF EXISTS dept11;
DROP TABLE IF EXISTS dept;
DROP TABLE IF EXISTS emp;
DROP TABLE IF EXISTS job;
DROP TABLE IF EXISTS salarygrade;
-- 部门表
CREATE TABLE dept (
id INT PRIMARY KEY PRIMARY KEY, -- 部门id
dname VARCHAR(50), -- 部门名称
loc VARCHAR(50) -- 部门所在地
);
-- 职务表，职务名称，职务描述
CREATE TABLE job (
id INT PRIMARY KEY,
jname VARCHAR(20),
description VARCHAR(50)
);
-- 员工表
CREATE TABLE emp (
id INT PRIMARY KEY, -- 员工id
ename VARCHAR(50), -- 员工姓名
job_id INT, -- 职务id
mgr INT , -- 上级领导
joindate DATE, -- 入职日期
salary DECIMAL(7,2), -- 工资
bonus DECIMAL(7,2), -- 奖金
dept_id INT, -- 所在部门编号
CONSTRAINT emp_jobid_ref_job_id_fk FOREIGN KEY (job_id) REFERENCES job (id),
CONSTRAINT emp_deptid_ref_dept_id_fk FOREIGN KEY (dept_id) REFERENCES dept (id)
);
-- 工资等级表
CREATE TABLE salarygrade (
grade INT PRIMARY KEY, -- 级别
losalary INT, -- 最低工资
hisalary INT -- 最高工资
);
-- 添加4个部门
INSERT INTO dept(id,dname,loc) VALUES
(10,'教研部','北京'),
(20,'学工部','上海'),
(30,'销售部','广州'),
(40,'财务部','深圳');
-- 添加4个职务
INSERT INTO job (id, jname, description) VALUES
(1, '董事长', '管理整个公司，接单'),
(2, '经理', '管理部门员工'),
(3, '销售员', '向客人推销产品'),
(4, '文员', '使用办公软件');
-- 添加员工
INSERT INTO emp(id,ename,job_id,mgr,joindate,salary,bonus,dept_id) VALUES
(1001,'孙悟空',4,1004,'2000-12-17','8000.00',NULL,20),
(1002,'卢俊义',3,1006,'2001-02-20','16000.00','3000.00',30),
(1003,'林冲',3,1006,'2001-02-22','12500.00','5000.00',30),
(1004,'唐僧',2,1009,'2001-04-02','29750.00',NULL,20),
(1005,'李逵',4,1006,'2001-09-28','12500.00','14000.00',30),
(1006,'宋江',2,1009,'2001-05-01','28500.00',NULL,30),
(1007,'刘备',2,1009,'2001-09-01','24500.00',NULL,10),
(1008,'猪八戒',4,1004,'2007-04-19','30000.00',NULL,20),
(1009,'罗贯中',1,NULL,'2001-11-17','50000.00',NULL,10),
(1010,'吴用',3,1006,'2001-09-08','15000.00','0.00',30),
(1011,'沙僧',4,1004,'2007-05-23','11000.00',NULL,20),
(1012,'李逵',4,1006,'2001-12-03','9500.00',NULL,30),
(1013,'小白龙',4,1004,'2001-12-03','30000.00',NULL,20),
(1014,'关羽',4,1007,'2002-01-23','13000.00',NULL,10);
-- 添加5个工资等级
INSERT INTO salarygrade(grade,losalary,hisalary) VALUES
(1,7000,12000),
(2,12010,14000),
(3,14010,20000),
(4,20010,30000),
(5,30010,99990);
/*
1.员工编号，员工姓名，工资 信息在emp 员工表中
2.职务名称，职务描述，信息在job职务表中
3.job职务表和emp员工表 是一对多的关系 emp.job_id =job.id
*/
-- 1.查询所有员工信息。查询员工编号，员工姓名，工资，职务名称，职务描述
-- 隐式内连接
select emp.id,emp.ename,emp.salary,job.jname,job.description from emp,job where emp.job_id=job.id order by id asc;
-- 显示内连接
select emp.id,emp.ename,emp.salary,job.jname,job.description from emp inner join job on emp.job_id=job.id order by id asc;
select* from emp;
select*from job;
-- 2.查询员工编号，员工姓名，工资，职务名称，职务描述，部门名称，部门位置
/*
1.员工编号，员工姓名，工资 信息在emp 员工表中
2.职务名称，职务描述，信息在job职务表中
3.job职务表和emp员工表 是一对多的关系 emp.job_id =job.id
4.部门名称，部门位置 来自于 部门表dept
5.dept和emp一对多关系dept.id=emp.dept_id
*/
SELECT
emp.id,
emp.ename,
emp.salary,
job.jname,
job.description,
dept.dname,
dept.loc
FROM
emp,
job,
dept
WHERE
emp.job_id = job.id
and dept.id=emp.dept_id
ORDER BY
id ASC;
-- 显示连链接
SELECT
emp.id,
emp.ename,
emp.salary,
job.jname,
job.description,
dept.dname,
dept.loc
FROM
emp
INNER JOIN
job
ON
emp.job_id = job.id
INNER JOIN
dept
ON
dept.id=emp.dept_id
ORDER BY
id ASC;
-- 3.查询员工姓名，工资，工资等级
/*
1.员工编号，员工姓名，工资 信息在emp 员工表中
2.工资等级 信息在salarygrade 职务表中
3.emp.salary>=salarygrade.losalary and emp.salary<=salarygrade.hisalary
*/
SELECT
emp.ename,
emp.salary,
t2.grade
FROM
emp,
salarygrade t2
WHERE
emp.salary >= t2.losalary
AND emp.salary <= t2.hisalary;
-- 4.查询员工姓名，工资，职务名称，职务描述，部门名称，部门位置，工资等级
SELECT
emp.ename,
emp.salary,
t2.grade
FROM
emp,
salarygrade t2
WHERE
emp.salary >= t2.losalary
AND emp.salary <= t2.hisalary;
SELECT
emp.id,
emp.ename,
emp.salary,
job.jname,
job.description,
dept.dname,
dept.loc
FROM
emp
INNER JOIN job on emp.job_id=job.id;
INNER JOIN job dept.id = emp.dept_id;
INNER JOIN salarygrade t2 on emp.salary between t2.salary and t2.hisalary;
-- 5.查询出部门编号、部门名称、部门位置、部门人数
/*
1.部门编号,部门名称，部门位置，来自于部门dept表
2.部门人数；在emp表中 按照dept_id进行分组，然后count(*)统计数量
3.使用子查询，让部门表和分组后的表进行内连接
*/
select*from dept;
select dept_id,count(*)from emp group by dept_id;
select*from dept,(select dept_id,count(*)from emp group by dept_id) t1 where dept.id=t1.dept_id;
