dongtangdao7232 2017-02-01 06:09
浏览 30
已采纳

不确定如何在mysql中使用php变量

This is returning a blank screen. What specifically do I have to do to test if a session variable is in the database and return the corresponding value from a different column?

$sql = "SELECT email FROM fgusers3
WHERE username = '$_SESSION['username']'";
$result = $conn->query($sql);
  • 写回答

3条回答 默认 最新

  • doujiang1993 2017-02-01 06:14
    关注

    The most correct way to use PHP variables in PHP is to use prepared statements.

    $query = $dbh->prepare("SELECT email FROM fgusers3 where username=:username")
    $query->execute(array(":username"=>$_SESION['username']));
    

    This is far superior to solution that involve direct string concatenation, and still better than solutions that involve string escaping.

    The reason that you should not use direct string concatenation as in some of the other answers is that it leads to SQL Injection. An attacker can easily gain complete access to your database by using carefully crafted strings.

    The above example uses PDO, which in my not very humble opinion is a far superior API to mysqli. Mysqli also has prepared statements It's usage is similar but the syntax is different.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
查看更多回答(2条)

报告相同问题?

悬赏问题

  • ¥15 如何在scanpy上做差异基因和通路富集?
  • ¥20 关于#硬件工程#的问题,请各位专家解答!
  • ¥15 关于#matlab#的问题:期望的系统闭环传递函数为G(s)=wn^2/s^2+2¢wn+wn^2阻尼系数¢=0.707,使系统具有较小的超调量
  • ¥15 FLUENT如何实现在堆积颗粒的上表面加载高斯热源
  • ¥30 截图中的mathematics程序转换成matlab
  • ¥15 动力学代码报错,维度不匹配
  • ¥15 Power query添加列问题
  • ¥50 Kubernetes&Fission&Eleasticsearch
  • ¥15 報錯:Person is not mapped,如何解決?
  • ¥15 c++头文件不能识别CDialog