mysql cmd客户端登录问题Access denied for user root@localhost错误解决方法:1. 管理员登陆系统,停止mysql服务或者结束mysqld-nt进程2. 进入命令行,来到mysql的安装目录.假设安装目录为 d:\mysql\ , CMD进入命令行3. 运行 d:\mysql\bin\mysqld-nt --skip-grant-tables 启动mysq
mysql开机自启动 安装完成后,启动Mysql。systemctl start mysqld.service设置root密码。update user set password=password("123456") where user='root';开机自启动。1 vim /etc/rc.local2 添加service mysqld start
MySQL IN/EXISTS优化问题where条件in操作,当子查询的条件中有IN操作时效率低下,sql语句:SELECT a.idFROM A aINNER JOIN B b ON a.id = b.idWHERE 条件AND a.id IN (SELECT c.id FROM C c LEFT JOIN D d ON c.id=d.id WHERE 条件)尝试EXISTS同样效率