-- 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;
-- 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;