MySQL 数据库示例：员工信息、薪资等级和部门管理

CREATE TABLE SALGRADE(
	GRADE bigint(20),
	LOSAL DECIMAL(8),
	HISAL DECIMAL(8),
	PRIMARY KEY (`GRADE`)
);
INSERT INTO SALGRADE VALUES(1,700,1200);
INSERT INTO SALGRADE VALUES (2, 1201, 1400);
INSERT INTO SALGRADE VALUES (3, 1401, 2000);
INSERT INTO SALGRADE VALUES (4, 2001, 3000);
INSERT INTO SALGRADE VALUES (5, 3001, 9999);


CREATE TABLE EMP(
	EMPNO BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT '编号',
	ENAME VARCHAR(10),
	JOB VARCHAR(9),
	MGR DECIMAL(4),
	HIREDATE DATE,
	SAL DECIMAL(7, 2),
	COMM DECIMAL(7, 2),
	DEPTNO BIGINT(20),
	PRIMARY KEY (`EMPNO`) USING BTREE
);

INSERT INTO EMP VALUES (7369, 'SMITH', 'CLERK', 7902, '1980-12-17', 800, NULL, 20);
INSERT INTO EMP VALUES (7499, 'ALLEN', 'SALESMAN', 7698, '1981-02-20', 1600, 300, 30);
INSERT INTO EMP VALUES (7521, 'WARD', 'SALESMAN', 7698, '1981-02-22',  1250, 500, 30);
INSERT INTO EMP VALUES (7566, 'JONES', 'MANAGER', 7839, '1981-04-02', 2975, NULL, 20);
INSERT INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN', 7698, '1981-09-28',  1250, 1400, 30);
INSERT INTO EMP VALUES (7698, 'BLAKE', 'MANAGER', 7839, '1981-05-01', 2850, NULL, 30);
INSERT INTO EMP VALUES (7782, 'CLARK', 'MANAGER', 7839, '1981-06-09',  2450, NULL, 10);
INSERT INTO EMP VALUES (7788, 'SCOTT', 'ANALYST', 7566, '1982-12-09',  3000, NULL, 20);
INSERT INTO EMP VALUES (7839, 'KING', 'PRESIDENT', NULL, '1981-11-17',5000, NULL, 10);
INSERT INTO EMP VALUES (7844, 'TURNER', 'SALESMAN', 7698, '1981-09-08',  1500, 0, 30);
INSERT INTO EMP VALUES (7876, 'ADAMS', 'CLERK', 7788, '1983-01-12',  1100, NULL, 20);
INSERT INTO EMP VALUES (7900, 'JAMES', 'CLERK', 7698, '1981-12-03', 950, NULL, 30);
INSERT INTO EMP VALUES (7902, 'FORD', 'ANALYST', 7566, '1981-12-03', 3000, NULL, 20);
INSERT INTO EMP VALUES (7934, 'MILLER', 'CLERK', 7782, '1982-01-23', 1300, NULL, 10);

-- 创建DEPT部门表
CREATE TABLE DEPT(
	DEPTNO BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT '编号',
	DNAME VARCHAR(14),
	LOC VARCHAR(13),
	PRIMARY KEY (`DEPTNO`) USING BTREE
);
-- DEPT部门表添加数据
INSERT INTO DEPT VALUES (10, 'ACCOUNTING', 'NEW YORK');
INSERT INTO DEPT VALUES (20, 'RESEARCH', 'DALLAS');
INSERT INTO DEPT VALUES (30, 'SALES', 'CHICAGO');
INSERT INTO DEPT VALUES (40, 'OPERATIONS', 'BOSTON');



CREATE TABLE SALGRADE_BAK AS SELECT * FROM SALGRADE;
CREATE TABLE EMP_BAK AS SELECT * FROM EMP;
CREATE TABLE DEPT_BAK AS SELECT * FROM DEPT;```