CREATE DATABASE test;
use test;
CREATE TABLE student (
ID INT PRIMARY KEY,
xh VARCHAR(20) COMMENT '学号',
xm VARCHAR(50) COMMENT '姓名',
xb VARCHAR(10) COMMENT '性别',
csny VARCHAR(20) COMMENT '出生年月',
nj INT COMMENT '年级',
xy VARCHAR(50) COMMENT '学院'
);
CREATE TABLE goods(
id INT(11) PRIMARY KEY AUTO_INCREMENT COMMENT '商品编号',
type VARCHAR(30) NOT NULL COMMENT '商品类别',
name VARCHAR(30) UNIQUE COMMENT '商品名称',
price DECIMAL(7,2) COMMENT '商品价格',
num INT(11) DEFAULT 0 COMMENT '商品库存',
add_time DATETIME COMMENT '添加时间'
);
INSERT INTO goods(id, type, name, price, num, add_time)
VALUES(1,'书籍','西游记',50.4,20,'2018-01-01 13:40:40'),
(2,'糖类','牛奶糖',2.5,200,'2018-02-02 13:40:40'),
(3,'糖类','水果糖',2.5,100,null),
(4,'服饰','休闲西服',800,null,'2018-04-04 13:40:40'),
(5,'饮品','果汁',3,70,'2018-05-05 13:40:40');
-- INSERT INTO student (ID, xh, xm, xb, csny, nj, xy) VALUES
-- (1, 'J171001', '张三丰', '男', '2001年3月', 21, '信息工程');
INSERT INTO student (ID, xh, xm, xb, csny, nj, xy) VALUES
(1, 'J171001', '张三丰', '男', '2001年3月', '21', '信息工程'),
(2, 'J171002', '李静', '女', '2001年2月', '21', '工商管理'),
(3, 'J171003', '张明', '男', '2001年3月', '21', '计算机科学与应用'),
(4, 'J1721001', '王丽', '女', '2002年6月', '22', '轮机工程'),
(5, 'J1721002', '李大成', '男', '2002年9月', '22', '机电工程'),
(6, 'J1721002', '张白云', '女', '2000年4月', '22', '艺术学院'),
(7, 'J1731003', '刘芳芳', '女', '2002年8月', '23', '材料学院'),
(8, 'J1731003', '赵明明', '男', '2001年12月', '23', '智能工程学院');
-- SELECT * FROM student;
-- SELECT stu.xh AS 'account',stu.xm AS 'name',stu.xb as 'gendar',
-- stu.csny AS 'birth', stu.nj AS 'grade', stu.xy as 'department'
-- FROM student AS stu WHERE stu.nj IN ('22','23');
-- 查询表中出生日期为2002年的记录
-- SELECT stu.xh AS 'account',stu.xm AS 'name',stu.xb as 'gendar',
-- stu.csny AS 'birth', stu.nj AS 'grade', stu.xy as 'department'
-- FROM student AS stu WHERE csny LIKE '2002%';
-- SELECT stu.xh AS 'account',stu.xm AS 'name',stu.xb as 'gendar',
-- stu.csny AS 'birth', stu.nj AS 'grade', stu.xy as 'department'
-- FROM student AS stu WHERE stu.xy LIKE '计算机科学与应用';
-- 查询表中男生、女生的数量
SELECT stu.xb AS gendar, COUNT(*) as '数量' FROM student AS stu GROUP BY stu.xb;
-- SELECT stu.xh AS 'account',stu.xm AS 'name',stu.xb as 'gendar',
-- stu.csny AS 'birth', stu.nj AS 'grade', stu.xy as 'department'
-- FROM student AS stu WHERE stu.xh= 'J1721001';
-- show tables;
INSERT INTO goods(id, type, name, price, num, add_time)
VALUES(6,'书籍','论语',109,50,'2018-01-03 13:40:40'),
(7,'水果','西瓜',1.5,null,'2018-02-05 13:40:40'),
(8,'水果','苹果',3,100,'2018-03-05 13:40:40'),
(9,'服饰','牛仔裤',120,10,'2018-05-04 13:40:40'),
(10,'书籍','红楼梦',50.5,15,'2018-05-06 13:40:40'),
(11,'书籍','红楼梦2',50.5,15,'2018-05-06 13:40:40');
-- SELECT * FROM goods;
-- SELECT * FROM goods ORDER BY price DESC;
-- SELECT id FROM goods;
-- SELECT COUNT(num) AS '有库存条目数' FROM goods;
-- SELECT COUNT(*) AS '条目数' FROM goods;
-- SELECT SUM(num) AS '所有库存' FROM goods;
-- SELECT type, AVG(price) AS '平均价格' FROM goods GROUP BY type;
-- SELECT MAX(price) AS '最高价格', MIN(price) AS '最低价格' FROM goods;
-- SELECT a.id, a.name, a.price FROM goods AS a WHERE a.type = '水果';
-- SELECT type,COUNT(type) AS '数量' FROM goods GROUP BY type;
CREATE TABLE course_records (
ID INT PRIMARY KEY,
name VARCHAR(50) COMMENT '学员姓名',
course_name VARCHAR(100) COMMENT '课程名称',
buy_time VARCHAR(20) COMMENT '购买课程时间',
view_duration INT COMMENT '观看时长(秒)',
play_times INT COMMENT '播放次数',
valid VARCHAR(10) COMMENT '是否有效',
last_score INT COMMENT '最近一次模拟考成绩'
);
INSERT INTO course_records (ID, name, course_name, buy_time, view_duration, play_times, valid, last_score) VALUES
(1, '张三丰', '数据采集(一)', '2023年10月', 3600, 5, '是', 90),
(2, '李静', '数据处理', '2022年11月', 3240, 4, '是', 85),
(3, '张明', '数据标注工程', '2023年11月', 1120, 3, '是', 72),
(4, '王丽', '数据分析', '2023年11月', 56, 2, '否', 60),
(5, '李大成', '数据采集(一)', '2023年11月', 8200, 6, '是', 98),
(6, '张白云', '数据采集(二)', '2023年12月', 450, 1, '是', 20),
(7, '刘芳芳', '机器学习', '2023年11月', 3980, 2, '是', 40),
(8, '赵明明', '机器学习', '2023年11月', 2500, 4, '是', 80);
-- SELECT * FROM course_records;
-- SELECT s.name AS '学生姓名', s.course_name as '课程名称' FROM course_records AS s;
-- SELECT s.name AS '学生姓名', s.course_name AS '课程名称' ,
-- s.valid AS '是否有效', s.view_duration AS '观看时长'
-- FROM course_records AS s
-- WHERE s.valid = '是';
-- SELECT s.name AS '学生姓名', s.course_name AS '课程名称' ,
-- s.valid AS '是否有效', s.view_duration AS '观看时长'
-- FROM course_records AS s
-- WHERE s.view_duration >1800;
-- SELECT s.name AS '学生姓名', s.course_name AS '课程名称' ,
-- s.valid AS '是否有效', s.view_duration AS '观看时长',
-- s.play_times AS '播放次数'
-- FROM course_records AS s
-- WHERE s.play_times>3;
-- SELECT s.name AS '学生姓名', s.course_name AS '课程名称' ,
-- s.valid AS '是否有效', s.view_duration AS '观看时长',
-- s.last_score AS '模考成绩'
-- FROM course_records AS s
-- -- WHERE s.last_score BETWEEN 60 AND 100;
-- WHERE s.last_score >=60 AND s.last_score <=100;
-- SELECT s.name AS '学生姓名', s.course_name AS '课程名称' ,
-- s.buy_time AS '购买课程时间', s.valid AS '是否有效',
-- s.view_duration AS '观看时长', s.last_score AS '模考成绩'
-- FROM course_records s
-- WHERE s.buy_time ='2023年11月' AND s.course_name = '机器学习';
-- SELECT s.name AS '学生姓名', s.course_name AS '课程名称' ,
-- s.buy_time AS '购买课程时间', s.play_times AS '累计播放次数',
-- s.valid AS '是否有效', s.view_duration AS '观看时长',
-- s.last_score AS '模考成绩'
-- FROM course_records s
-- WHERE s.course_name = '数据采集(一)' AND s.valid = '是';