从每个字段的列中获取值，但它返回NULL？

Question

我想从我的数据库中的列回合得到“回合”的价值。所以，我想为每个辩论/帖子获得一个字段的值（1-5）。基于价值/数量，它应该显示不同的东西。当我认为它的值为NULL时，即使该辩论/帖子的db字段值是4.这不仅仅是辩论，但是对于所有这些都会发生。如何获得列中字段的实际值并将其分配给名为$ rounds的变量。这个变量需要具有每次辩论的价值，而不仅仅是辩论。

<?php 
$servername = ""; 
$username = ""; 
$password = ""; 
$dbname = ""; 

$con = new mysqli($servername, $username, $password, $dbname); 

if ($con->connect_error) { 
    die("Connection failed: " . $con->connect_error); 
} 
else{ 
    $sql = "SELECT rounds FROM vf_Discussion"; 
    $result = $con->query($sql); 

    $allRounds = $result->fetch_row(); 
    $rounds = $allRounds[0]; 

    var_dump($rounds); 

} 
    mysqli_close($con); 

     $rounds1 =  '<h2 class="CommentHeading">Round 1 (Pro)</h2> <br> <h2 class="CommentHeading">Round 1 (Con) </h2>'; 

     $rounds2 = '<h2 class="CommentHeading">Round 2 (Pro)</h2> <br> <h2 class="CommentHeading">Round 2 (Con)</h2>'; 

     $rounds3 = '<h2 class="CommentHeading">Round 3 (Pro)</h2> <br> <h2 class="CommentHeading">Round 3 (Con)</h2>'; 

     $rounds4 =  '<h2 class="CommentHeading">Round 4 (Pro)</h2> <br> <h2 class="CommentHeading">Round 4 (Con)</h2>'; 

     $rounds5 = '<h2 class="CommentHeading">Round 5 (Pro)</h2> <br> <h2 class="CommentHeading">Round 5 (Con)</h2>'; 

    foreach($allRounds as $rounds) { 
     if ($rounds == 1) { 
      echo $rounds1; 
      foreach ($Sender->Data('Answers') as $Row) { 
       $Sender->EventArguments['Comment'] = $Row; 
       WriteComment($Row, $Sender, Gdn::Session(), 0); 
      } 
     } 
     if ($rounds == 2) { 
      echo $rounds1; 
      echo $rounds2; 
      foreach ($Sender->Data('Answers') as $Row) { 
       $Sender->EventArguments['Comment'] = $Row; 
       WriteComment($Row, $Sender, Gdn::Session(), 0); 
      } 
     } 
     if ($rounds == 3) { 
      echo $rounds1; 
      echo $rounds2; 
      echo $rounds3; 
      foreach ($Sender->Data('Answers') as $Row) { 
       $Sender->EventArguments['Comment'] = $Row; 
       WriteComment($Row, $Sender, Gdn::Session(), 0); 
      } 
     } 
     if ($rounds == 4) { 
      echo $rounds1; 
      echo $rounds2; 
      echo $rounds3; 
      echo $rounds4; 
      foreach ($Sender->Data('Answers') as $Row) { 
       $Sender->EventArguments['Comment'] = $Row; 
       WriteComment($Row, $Sender, Gdn::Session(), 0); 
      } 
     } 
     if ($rounds == 5) { 
      echo $rounds1; 
      echo $rounds2; 
      echo $rounds3; 
      echo $rounds4; 
      echo $rounds5; 
      foreach ($Sender->Data('Answers') as $Row) { 
       $Sender->EventArguments['Comment'] = $Row; 
       WriteComment($Row, $Sender, Gdn::Session(), 0); 
     } 
    } 

    } 
     ?> 

Answer 1

您应该通过对象

<?php 







    $servername = ""; 
    $username = ""; 
    $password = ""; 
    $dbname = ""; 


    $con = new mysqli($servername, $username, $password, $dbname); 

    if ($con->connect_error) { 
     die("Connection failed: " . $con->connect_error); 
    } 
    else{ 
     $sql = "SELECT rounds FROM vf_Discussion"; 
     $result = $con->query($sql); 


     while($row = mysql_fetch_array($result)) 
     { 

      var_dump($row); 
    } 




    }