一. 表关系 1. 创建如下表，并创建相关约束. # 创建班级表 create table class (cid int primary key not null auto_increment,caption varchar(20) not null );# 创建老师表 create table teacher (tid int primary key not null auto_increment,tname varchar(20) not null );# 创建学生表 create table student (sid int primary key not null auto_increment,sname varchar(20) not null,gender enum("男", "女"),class_id in...
综合练习题 表结构 整合一下方便查看 teacher student coursescors练习题 1、自行创建测试数据 create table student(sid int primary key auto_increment,sname char(32),gender enum("女","男"),class_id int,constraint fk_class_id foreign key (class_id) references class(cid)on DELETE cascadeon update cascade );create table teacher(tid int primary key auto_increment,tname char(32) )；create table class(cid ...
#建学生信息表student create table student ( sno varchar(20) not null primary key, sname varchar(20) not null, ssex varchar(20) not null, sbirthday datetime, class varchar(20)); #建立教师表 create table teacher ( tno varchar(20) not null primary key, tname varchar(20) not null, tsex varchar(20) not null, tbirthday datetime, prof varchar(20), depart varchar(20) not null); #建立课程表course create ta...
取出价格里面最大的前三个值 SELECT price FROM t_book ORDER BY price DESC LIMIT 3;查询两门及两门以上不及格的学生的平均分。SELECT name,AVG(chengji) FROM student1 GROUP BY name HAVING SUM(chengji < 60) >= 2;select student_id,avg(number) from score where student_id in (select student_id from score where number < 60 group by student_id having count(corse_id) >=1) group by student_id;求选了课程的学生人数...
MySQL练习题参考答案 ?导出现有数据库数据：mysqldump -u用户名 -p密码 数据库名称 >导出文件路径 # 结构+数据 mysqldump -u用户名 -p密码 -d 数据库名称 >导出文件路径 # 结构 导入现有数据库数据：mysqldump -uroot -p密码 数据库名称 < 文件路径 /*Navicat Premium Data TransferSource Server : localhostSource Server Type : MySQLSource Server Version : 50624Source Host : local...
表结构如图所示 -- MySQL dump 10.13 Distrib 5.7.23, for Win64 (x86_64) -- -- Host: localhost Database: db -- ------------------------------------------------------ -- Server version 5.7.23/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */; /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */; /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */; /*!4...