MySQL数据库单表练习

练习1

CREATE TABLE product(
	pid INT PRIMARY KEY,#主键ID
	pname VARCHAR(20),#商品名称
	price DOUBLE,#商品价格
	category_name VARCHAR(32)#商品分类名称
);

INSERT INTO product(pid,pname,price,category_name) VALUES(1,'联想电脑',5000,'电脑办公');
INSERT INTO product(pid,pname,price,category_name) VALUES(2,'海尔电脑',3000,'电脑办公');
INSERT INTO product(pid,pname,price,category_name) VALUES(3,'雷神电脑',5000,'电脑办公');

INSERT INTO product(pid,pname,price,category_name) VALUES(4,'JACK JONES',800,'服装');
INSERT INTO product(pid,pname,price,category_name) VALUES(5,'真维斯',200,'服装');
INSERT INTO product(pid,pname,price,category_name) VALUES(6,'花花公子',440,'服装');
INSERT INTO product(pid,pname,price,category_name) VALUES(7,'劲霸',2000,'服装');

INSERT INTO product(pid,pname,price,category_name) VALUES(8,'香奈儿',800,'女士用品');
INSERT INTO product(pid,pname,price,category_name) VALUES(9,'相宜本草',200,'女士用品');
INSERT INTO product(pid,pname,price,category_name) VALUES(10,'面霸',5,'女士用品');

INSERT INTO product(pid,pname,price,category_name) VALUES(11,'雪碧',56,'饮料饮品');
INSERT INTO product(pid,pname,price,category_name) VALUES(12,'香飘飘奶茶',1,'饮料饮品');

INSERT INTO product(pid,pname,price,category_name) VALUES(13,'iPhone9',8000,NULL);

#查询product表中所有记录
SELECT * FROM product

#查询product表中pid和pname字段
SELECT pid,pname FROM product

#查询product表中所有的电脑办公记录
SELECT * FROM product WHERE category_name="电脑办公"

#查询结果是表达式（运算查询）：将所有商品的价格+10元进行显示.
SELECT pname AS "名称",price+10 AS "价格" FROM product

#查询商品名称为“花花公子”的商品所有信息：
SELECT *FROM product WHERE pname="花花公子"

#查询价格为800商品
SELECT *FROM product WHERE price=800

#查询价格不是800的所有商品
SELECT *FROM product WHERE price!=800

#查询商品价格大于60元的所有商品信息
SELECT *FROM product WHERE price>60

#查询商品价格在200到1000之间所有商品
SELECT *FROM product WHERE price>200 AND price <1000
SELECT *FROM product WHERE price>200 && price <1000
SELECT *FROM product WHERE price BETWEEN 200 AND 1000

#查询商品价格是200或800或者2000的所有商品
SELECT *FROM product WHERE price=20 OR price=800 OR price=2000
SELECT *FROM product WHERE price=20|| price=800 || price=2000
SELECT *FROM product WHERE price IN(20,800,2000)

#查询含有'霸'字的所有商品
SELECT *FROM product WHERE pname LIKE '%霸%'

#查询以'香'开头的所有商品
SELECT *FROM product WHERE pname LIKE '香%'

#查询第二个字为'想'的所有商品
SELECT *FROM product WHERE pname LIKE '_想%'

#商品没有分类的商品
SELECT *FROM product WHERE category_name IS NULL

#查询有分类的商品
SELECT *FROM product WHERE category_name IS NOT NULL

#1.使用价格排序(降序)
SELECT *FROM product ORDER BY price DESC

#2.在价格排序(降序)的基础上
#若价格相同，相同价格的数据以pid降序排序
SELECT *FROM product ORDER BY price DESC,pid ASC

#1 查询商品的总条数
#查看商品总价格、最大价格、最小价格、价格的平均值
SELECT SUM(price) AS "总价格",MAX(price),MIN(price),AVG(price) FROM product

#2 查询价格大于200商品的总条数product
SELECT COUNT(1) FROM product WHERE price >200

#3 查询分类为'电脑办公'的所有商品的总记录
SELECT COUNT(1) FROM product WHERE category_name="电脑办公"

#4 查询分类为'服装'所有商品的平均价格
SELECT AVG(price) FROM product WHERE category_name="服装"

# 统计各个分类下商品的个数
SELECT * FROM product WHERE pid<=2

SELECT * FROM product LIMIT 4,2
找id=5 他在第三页(3-1)*2=4 （索引始为零）

#统计各个分类商品的个数，有且 只显示分类名称不为空值的数据
SELECT * FROM product WHERE category_name="女士用品" GROUP BY category_name HAVING category_name 
IS NOT NULL ORDER BY pid ASC LIMIT 0,6

 

练习2

CREATE TABLE s (
	sid	CHAR(6),
	sname		VARCHAR(50),
	age		INT,
	gender	VARCHAR(50)
);

INSERT INTO s VALUES('S_1001', 'liuYi', 35, 'male');
INSERT INTO s VALUES('S_1002', 'chenEr', 15, 'female');
INSERT INTO s VALUES('S_1003', 'zhangSan', 95, 'male');
INSERT INTO s VALUES('S_1004', 'liSi', 65, 'female');
INSERT INTO s VALUES('S_1005', 'wangWu', 55, 'male');
INSERT INTO s VALUES('S_1006', 'zhaoLiu', 75, 'female');
INSERT INTO s VALUES('S_1007', 'sunQi', 25, 'male');
INSERT INTO s VALUES('S_1008', 'zhouBa', 45, 'female');
INSERT INTO s VALUES('S_1009', 'wuJiu', 85, 'male');
INSERT INTO s VALUES('S_1010', 'zhengShi', 5, 'female');
INSERT INTO s VALUES('S_1011', 'xxx', NULL, NULL);

-- 　查询性别为女，并且年龄大于等于50的记录
SELECT *FROM s WHERE gender="female"&&age>50
-- 　查询学号为S_1001，或者姓名为liSi的记录
SELECT *FROM s WHERE sid="s_1001" ||sname="liSi"
-- 　查询学号为S_1001，S_1002，S_1003的记录
SELECT *FROM s WHERE sid="S_1001" OR sid="S_1002" OR sid="S_1003"
-- 　查询学号不是S_1001，S_1002，S_1003的记录
SELECT *FROM s WHERE sid!="S_1001" && sid!="S_1002" && sid!="S_1003"
-- 　查询年龄为null的记录
SELECT *FROM s WHERE age IS NULL
-- 　查询年龄在20到40之间的学生记录
SELECT *FROM s WHERE age>20&&age<=40
-- 　查询性别非男的学生记录
SELECT *FROM s WHERE gender!="male"
-- 　查询姓名不为null的学生记录
SELECT *FROM s WHERE sname IS NOT NULL
-- 　查询姓名由5个字母构成的学生记录
SELECT *FROM s 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 s WHERE sname LIKE "_____" &&sname NOT LIKE "____i"
-- 　查询姓名以“z”开头的学生记录
SELECT *FROM s WHERE sname LIKE "z%"
-- 　查询姓名中第2个字母为“i”的学生记录
SELECT *FROM s WHERE sname LIKE "_i%"
-- 　查询姓名中包含“a”字母的学生记录
SELECT *FROM s WHERE sname LIKE "%a%"

 

练习3

CREATE DATABASE test1;
USE test1;

##部门表
#DROP IF EXISTS TABLE DEPT;
CREATE TABLE DEPT(
	DEPTNO INT  PRIMARY KEY,##部门编号
	DNAME VARCHAR(14) ,	##部门名称
	LOC VARCHAR(13)  	##部门地址
	) ;

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');
	
##员工表	
#DROP IF EXISTS TABLE EMP;
CREATE TABLE EMP(
	EMPNO INT  PRIMARY KEY,	#员工编号
	ENAME VARCHAR(10),	#员工姓名
	JOB VARCHAR(9),		#员工工作
	MGR INT, 		#员工直属领导编号
	HIREDATE DATE, 		#入职时间
	SAL DOUBLE,		#工资
	COMM DOUBLE,		#奖金
	DEPTNO INT		#对应dept表的外键
);  
## 添加 部门 和 员工 之间的主外键关系
ALTER TABLE EMP ADD CONSTRAINT FOREIGN KEY EMP(DEPTNO) REFERENCES DEPT (DEPTNO);

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,'1987-07-03',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,'1987-07-13',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,'1981-01-23',1300,NULL,10);

#1.查找部门是30的员工详细信息。
SELECT * FROM emp WHERE DEPTNO="30"

#2.找出从事clerk工作的员工的编号、姓名、部门号。
SELECT EMPNO,ENAME,JOB FROM emp WHERE JOB="CLERK"

#3.检索出奖金多于基本工资的员工信息。
SELECT * FROM emp WHERE COMM>SAL

#4.检索出奖金多于基本工资60%的员工信息。
SELECT * FROM emp WHERE comm>(SAL*0.6)

#5.找出10部门的经理、20部门的职员 的员工信息。
SELECT * FROM emp WHERE DEPTNO=10&&JOB="MANAGER"||DEPTNO=20&&JOB="CLERK"

#6.找出10部门的经理、20部门的职员 或者既不是经理也不是职员但是工资高于2000元的员工信息。
SELECT * FROM emp WHERE DEPTNO=10&&JOB="MANAGER"||DEPTNO=20&&JOB="CLERK"||JOB!="MANAGER"&&JOB!="CLERK"&&SAL>2000

#7.找出获得奖金的员工的信息。
SELECT * FROM emp WHERE COMM!=""

#8.找出奖金少于100或者没有获得奖金的员工的信息。
SELECT * FROM emp WHERE COMM<100||COMM IS NULL||COMM=""

#9.找出姓名以A、B、S开始的员工信息。
SELECT * FROM emp WHERE ENAME LIKE "A%"||ENAME LIKE "B%"||ENAME LIKE "C%"

#10.找到名字长度为6个字符的员工信息。
SELECT * FROM emp WHERE ENAME LIKE "______"

#11.名字中不包含R字符的员工信息。
SELECT * FROM emp WHERE ENAME NOT LIKE "%R%"

#12.返回员工的详细信息并按姓名排序。
SELECT * FROM emp ORDER BY ENAME ASC

#13.返回员工的信息并按工作降序工资升序排列。
SELECT * FROM emp ORDER BY SAL ASC,ENAME DESC

#14.计算员工的日薪(按30天)。
SELECT ENAME,(SAL/30) FROM emp

#15.找出姓名中包含A的员工信息。
SELECT * FROM emp WHERE ENAME LIKE "%A%"