1. 下载mysql的c客户端驱动：

地址：https://downloads.mysql.com/archives/c-c/

2. 修改mysql的用户密码为mysql_native_password模式：

ALTER USER root@localhost IDENTIFIED WITH mysql_native_password BY '111111';

3.修改mysql服务器的配置文件：my.ini

[mysqld]

skip_ssl

authentication_policy=mysql_native_password,,

4. 重启mysql服务器

5. 把mysql的c客户端驱动压缩包里的 libmysql.dll复制到 Qt5.6.3\5.6.3\msvc2015\bin 目录下

6. 编写qt测试代码测试

	QSqlDatabase dbSQL=QSqlDatabase::addDatabase("QMYSQL");
	dbSQL.setHostName(_HostName);
    dbSQL.setPort(_Port);
    dbSQL.setDatabaseName(_DatabaseName);
    dbSQL.setUserName(_UserName);
    dbSQL.setPassword(_Password);
    if(dbSQL.open() )
    {
    	QSqlQuery query;
        query.prepare("select count(1) from user");
        query.exec();
        int n=-1;
        while(query.next())
        {
            n = query.value(0).toInt();
            qDebug()<<"结果集"<<n;
        }
        if( n >0)
            qDebug() << "登陆成功！";
        else
            qDebug() << "登陆失败！";

        db->Close(); //关闭数据库
    }else{
    	qDebug() << "数据库载入失败!";
    ]