PHP如果在POST中仅加载第一个if

Question

我有这个代码：

    if(isset($_POST['remove'])){

                      $con = mysqli_connect(".","","","");

                $q = mysqli_query($con,"UPDATE members SET picture = '' WHERE username = '".$_SESSION['username']."'");

        header( "refresh:2;url=settings.php" );
        echo "<div class='notemarg'>Profile Picture has been removed. Refreshing page within 3 seconds...</div>";
}

它正在工作，但是我希望它做这样的事情

    if(isset($_POST['remove'])){

                      $con = mysqli_connect("","","","");
        while($row = mysqli_fetch_assoc($q)){
                                    if($row['picture'] == ""){
                                echo "<div class='notemarg'> No pictures to delete</div>";
        } else {
                $q = mysqli_query($con,"UPDATE members SET picture = '' WHERE username = '".$_SESSION['username']."'");

        header( "refresh:2;url=settings.php" );
        echo "<div class='notemarg'>Profile Picture has been removed. Refreshing page within 3 seconds...</div>";
        }
        }
}

这意味着仅当有图片时才会从数据库中删除图片。.如果没有，它将显示该消息“没有要删除的图片”……但它不起作用。它仍然显示该错误消息即使数据库中没有空白行也没有图片，因此它也不会删除行中的信息...问题出在哪里？ 顺便说一句：第一个代码可以正常工作，即使数据库中没有任何内容，它也可以工作，因此“个人资料图片已被删除”有点没有意义。 正在显示...

Answer 1

尝试以下方法：

  $con = mysqli_connect("","","","");
 if(isset($_POST['remove'])){

   $q = mysqli_query($con, "SELECT picutre FROM members where username = '". $_SESSION['username']. "'");          
   $row = mysqli_fetch_assoc($q);
   if( empty($row['picture'])){
      echo "<div class='notemarg'> No pictures to delete</div>";
   } 
   else {
     $q = mysqli_query($con,"UPDATE members SET picture = '' WHERE username = '".$_SESSION['username']."'");

     header( "refresh:2;url=settings.php" );
     echo "<div class='notemarg'>Profile Picture has been removed. Refreshing page within 3 seconds...</div>";
    }
 }

Answer 2

您需要mysqli_query语句：

$con = mysqli_connect("","","","");
if(isset($_POST['remove'])){
    $q = mysqli_query($con,"SELECT IFNULL(picture,'') AS picture
                        FROM members 
                        WHERE username = '".$_SESSION['username']."'");
    $row = mysqli_fetch_assoc($q);
    if( empty($row['picture'])){
      echo "<div class='notemarg'> No pictures to delete</div>";
    } 
    else {
      $q = mysqli_query($con,"UPDATE members SET picture = '' WHERE username = '".$_SESSION['username']."'");

      header( "refresh:2;url=settings.php" );
      echo "<div class='notemarg'>Profile Picture has been removed. Refreshing page within 3 seconds...</div>";
    }
 }