QString sql=QString("select username,password from users where username=1% and password=2%").arg(username).arg(password);
//QString sql= "select username,password from users where username = '"+username + "'and password ='" + password + "'";
就是做一个查询语句然后对应的账号密码对就可以登入进去,否则不行,谢谢了,不知道哪里写错了!(补充说明:是 MS SQL server)