MySQL 的相关语句（增删改查）（SQLyog软件实现）

-- 创建雇员表：emp
CREATE TABLE emp(
    empno        INT,        -- 员工编号
    ename        VARCHAR(50),    -- 员工姓名
    job        VARCHAR(50),    -- 员工工作
    mgr        INT,        -- 领导编号
    hiredate    DATE,        -- 入职日期
    sal        DECIMAL(7,2),    -- 月薪
    comm        DECIMAL(7,2),    -- 奖金
    deptno        INT        -- 部分编号
) ;

-- 添加数据
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,'1987-04-19',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,'1987-05-23',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);

-- 创建学生信息表：stu
CREATE TABLE stu(
    sid    CHAR(6),    -- 学生学号
    sname    VARCHAR(50),    -- 学生姓名
    age    INT,        -- 学生年龄
    gender    VARCHAR(50)    -- 学生性别
);

-- 添加数据
INSERT INTO stu VALUES('S_1001', 'liuYi', 35, 'male');
INSERT INTO stu VALUES('S_1002', 'chenEr', 15, 'female');
INSERT INTO stu VALUES('S_1003', 'zhangSan', 95, 'male');
INSERT INTO stu VALUES('S_1004', 'liSi', 65, 'female');
INSERT INTO stu VALUES('S_1005', 'wangWu', 55, 'male');
INSERT INTO stu VALUES('S_1006', 'zhaoLiu', 75, 'female');
INSERT INTO stu VALUES('S_1007', 'sunQi', 25, 'male');
INSERT INTO stu VALUES('S_1008', 'zhouBa', 45, 'female');
INSERT INTO stu VALUES('S_1009', 'wuJiu', 85, 'male');
INSERT INTO stu VALUES('S_1010', 'zhengShi', 50, 'female');
INSERT INTO stu VALUES('S_1011', 'xxx', NULL, NULL);

-- 创建部分表：dept
CREATE TABLE dept(
    deptno    INT,        -- 部分编码
    dname    VARCHAR(14),    -- 部分名称
    loc    VARCHAR(13)    -- 部分所在地点
);

-- 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');

-- 查询所有列
SELECT * FROM stu;

-- 删除数据
DELETE FROM stu WHERE sid = 'sunQi' ;

-- 查询指定列
SELECT sname,age FROM stu;

-- 查询性别为女，并且年龄为50的记录
SELECT * FROM stu WHERE gender='female' AND age=50;

-- 查询学号为S_1001，或者姓名为liSi的记录
SELECT * FROM stu WHERE sid='s_1001' OR sname='lisi';

-- 查询学号为S_1001，S_1002，S_1003的记录
SELECT * FROM stu WHERE sid IN ('s_1001','s_1002','s_1003' );

-- 查询学号不是S_1001，S_1002，S_1003的记录
SELECT * FROM stu WHERE sid NOT IN ('s_1001','s_1002','s_1003' );

-- 查询年龄为null的记录
SELECT * FROM stu WHERE age IS NULL;

-- 查询年龄在20到40之间的学生记录
SELECT * FROM stu WHERE age BETWEEN 20 AND 40; -- 或者
SELECT * FROM stu WHERE age>=20 AND age<=40;

-- 查询性别非男的学生记录
SELECT * FROM stu WHERE gender !='male'; -- 或者
SELECT * FROM stu WHERE gender <>'male';

-- 查询姓名不为null的学生记录
SELECT * FROM stu WHERE sname IS NOT NULL; -- 或者
SELECT * FROM stu WHERE NOT sname IS NULL;

-- 查询姓名由5个字母构成的学生记录
SELECT * FROM stu WHERE sname LIKE '_____';

-- 查询姓名由5个字母构成，并且第5个字母为“i”的学生记录
SELECT * FROM stu WHERE sname LIKE '____i';

-- 查询姓名以“z”开头的学生记录
SELECT * FROM stu WHERE sname LIKE 'z%';

-- 查询姓名中第2个字母为“i”的学生记录
SELECT * FROM stu WHERE sname LIKE '_i%';

-- 查询姓名中包含“a”字母的学生记录
SELECT * FROM stu WHERE sname LIKE '%a%';

-- 去除重复记录
SELECT DISTINCT * FROM stu;

-- 查询所有列
SELECT * FROM emp;

-- 查看雇员的月薪与佣金之和
SELECT *,sal+comm FROM emp; -- 或者
SELECT *,sal+IFNULL(comm,0) FROM emp;

-- 给列名添加别名
SELECT *, sal+IFNULL(comm,0) AS total FROM emp; -- 或者
SELECT *,sal+IFNULL(comm,0) total FROM emp;

-- 查询所有学生记录，按年龄升序排序
SELECT * FROM stu ORDER BY age;
SELECT * FROM stu ORDER BY age ASC;

-- 查询所有学生记录，按年龄降序排序
SELECT * FROM stu ORDER BY age DESC;

-- 查询所有雇员，按月薪降序排序，如果月薪相同时，按编号升序排序
SELECT * FROM emp ORDER BY sal DESC,empno ASC;

-- 查询emp表中记录数
SELECT COUNT(*) AS cnt FROM emp;

-- 查询emp表中有佣金的人数
SELECT COUNT(comm) AS cnt FROM emp;

-- 查询emp表中月薪大于2500的人数
SELECT COUNT(*) AS cnt FROM emp WHERE sal > 2500;

-- 统计月薪与佣金之和大于2500元的人数
SELECT COUNT(*) AS cnt FROM emp WHERE sal+IFNULL(comm,0) > 2500;

-- 查询有佣金的人数，以及有领导的人数
SELECT COUNT(comm), COUNT(mgr) FROM emp;

-- 查询所有雇员月薪和
SELECT SUM(sal) FROM emp;

-- 查询所有雇员月薪和，以及所有雇员佣金和
SELECT SUM(sal),SUM(comm) FROM emp;

-- 查询所有雇员月薪+佣金和
SELECT SUM(sal+IFNULL(comm,0)) FROM emp;

-- 统计所有员工平均工资
SELECT AVG(sal) FROM emp;

-- 查询最高工资和最低工资
SELECT MAX(sal),MIN(sal) FROM emp;

-- 查询每个部门的部门编号和每个部门的工资和
SELECT deptno, SUM(sal) FROM emp GROUP BY deptno;

-- 查询每个部门的部门编号以及每个部门的人数
SELECT deptno, COUNT(*) AS cnt FROM emp GROUP BY deptno;

-- 查询每个部门的部门编号以及每个部门工资大于1500的人数
SELECT deptno, COUNT(*) FROM emp WHERE sal>1500 GROUP BY deptno;

-- 查询工资总和大于9000的部门编号以及工资和
SELECT deptno, SUM(sal) FROM emp GROUP BY deptno HAVING SUM(sal) > 9000;

-- 

-- 查询所有列
SELECT * FROM dept;

-- 创建学生信息表 student
CREATE TABLE student(
    sid         INT,        -- 学号
    sname         VARCHAR(20),    -- 姓名
    age        INT,        -- 年龄
    scores        INT,        -- 成绩
    gender        VARCHAR(6),    -- 性别
    birthday    DATE        -- 出生日期
);

-- 添加数据
INSERT INTO student(sid,sname,age,scores,gender) VALUES (0001,'张华',23,49,'女');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (0007,'孙萌',20,59,'女','1997-02-24');
INSERT INTO student(sid,sname,age,scores,gender) VALUES (0002,'李四',28,69,'男');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (0009,'吴笑清',22,68,'女','1994-11-02');
INSERT INTO student(sid,sname,age,scores,gender) VALUES (0003,'王小花',26,29,'女');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (0004,'赵六',22,85,'男','1990-12-17');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (0005,'钱雨',21,87,'女','1992-03-30');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (0006,'李四',25,83,'男','1996-05-13');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (0008,'周董',27,99,'男','1995-07-23');
INSERT INTO student(sid,sname,age,scores,gender,birthday) VALUES (00010,'郑源',27,79,'男','1994-08-23');

-- 查询所有列
SELECT * FROM student;

-- 删除表 student
DROP TABLE student;

-- 去除重复记录
SELECT DISTINCT * FROM student;

-- 显示mydb下的所有表
USE mydb; SHOW TABLES;

-- 

-- 创建表：定义列之后独立指定主键
CREATE TABLE stu1(
    sid        CHAR(6),
    sname    VARCHAR(20),
    age        INT,
    gender    VARCHAR(10),
    PRIMARY KEY(sid)
);

-- 创建表：指定主键且自增长
CREATE TABLE stu11(
    sid    INT(6) PRIMARY KEY AUTO_INCREMENT,
    sname    VARCHAR(20),
    age    INT,
    gender    VARCHAR(10)
);

-- 添加数据（表：stu1或者stu11）
INSERT INTO stu11(sname,age,gender) VALUE ('张三',23,'男');
INSERT INTO stu11(sname,age,gender) VALUE ('李四',24,'男');
INSERT INTO stu11(sname,age,gender) VALUE ('李思思',26,'女');
INSERT INTO stu11(sname,age,gender) VALUE ('景甜',27,'女');
INSERT INTO stu11(sname,age,gender) VALUE ('刘亦菲',29,'女');
INSERT INTO stu11(sname,age,gender) VALUE ('刘诗诗',25,'女');

-- 删除数据
DELETE FROM stu11 WHERE sname='刘诗诗';

-- 查询所有列
SELECT * FROM stu11;

-- 修改表时指定主键
ALTER TABLE stu ADD PRIMARY KEY(sid);

-- 修改表时设置主键自增长
ALTER TABLE stu11 CHANGE sid sid INT AUTO_INCREMENT;

-- 修改表时删除主键自增长
ALTER TABLE stu11 CHANGE sid sid INT;

-- 删除主键（只是删除主键约束，而不会删除主键列）
ALTER TABLE stu DROP PRIMARY KEY;

-- 

-- 创建用户信息表 user,并指定主键且自增长
CREATE TABLE USER(
    uid        INT PRIMARY KEY AUTO_INCREMENT,
    username    VARCHAR(32),
    userpassword    VARCHAR(32)
);

-- 查询所有列
SELECT * FROM USER;

-- 删除表
DROP TABLE USER;

-- 添加数据
INSERT INTO USER(username,userpassword) VALUE ('zhangsan','');
INSERT INTO USER(username,userpassword) VALUE ('lisi','');
INSERT INTO USER(username,userpassword) VALUE ('wangwu','');
INSERT INTO USER(username,userpassword) VALUE ('zhaoliu','');
INSERT INTO USER(username,userpassword) VALUE ('sisi','');

-- 删除数据
DELETE FROM USER WHERE username='lisi';