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数据表介绍 1.学⽣表 Student(SId,Sname,Sage,Ssex) SId 学⽣编号 Sname 学⽣姓名 Sage 出⽣年⽉ Ssex 学⽣性别 2.课程表 Course(CId,Cname,TId) CId 课程编号 Cname 课程名称 TId 教师编号 3.教师表 Teacher(TId,Tname) TId 教师编号 Tn

mysql> select rand();+--------------------+| rand() |+--------------------+| 0.7015205088085686 |+--------------------+1 row in set (0.00 sec)mysql> select floor(1.23);+-------------+| floor(1.23) |+-------------+| .

mysql> create database db3;Query OK, 1 row affected (0.00 sec)mysql> create database if not exists db3;Query OK, 1 row affected, 1 warning (0.00 sec)mysql> drop database if exists db3;Query OK, 0 rows affected (0.01 sec)mysql> show .

安装mysql5.7 下载yum Repository 如果没有wget命令，则可以使用yum install wget wget -i -c http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm Centos换源 1. 备份 mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup