如何只删除分配给该值的行？（不知道标题怎么写）

Question

我正在尝试制作 post 系统。一切都运行良好，但有一件事我无法弄清楚...... 我在数据库中有一些行是我用准备好的 mysqli 提取的。好吧，当我回显行的值时，它显示了正确的回显，并且显示了所有列（这显然应该这样做），这很好。 SQL :

SELECT id,postby,downvotes,upvotes FROM posts

绑定结果如下：

bind_result($postid,$postby,$downvotes,$upvotes);

所以它正在工作。他们都被回声拉了出来。不错。

但是！当我试图从准备好的 mysqli 中删除 table 中的任何行（只有一行）时，它会删除所有行... 我的删除行代码：

DELETE FROM posts WHERE id = ?

和绑定参数如

bind_param('i',$postid);

但这会删除数据库中的所有行。我希望它只删除分配给 id 的那个。因此，如果它从数据库中拉出 20 行，它将删除数据库中的所有行...如何只删除分配给它的 id 的一行？谢谢！

我不得不提一下，我已经尝试过 <input name='deletesomething' type='hidden' value='<php? echo $postid ?>'> 之类的东西，然后又尝试了

之类的东西

bind_param('s',$_POST['deletesomething']);

但它仍然删除了所有行。如何解决？

编辑

对不起！实际上隐藏输入的方法是可行的，但是它非常不安全，因为用户可以更改值并且它会删除不同的行...

编辑 2

我的完整代码可以理解我真正想做什么。

<?php
$selectposts = "SELECT postby,posttxt,time,upvotes,downvotes,id FROM posts ORDER BY id DESC";
$stmt = $mysqli->prepare($selectposts);
$stmt->execute();
$stmt->bind_result($postby,$posttxt,$posttime,$upvotesdb,$downvotesdb,$postid);
$stmt->store_result();
while($stmt->fetch()){
   $picturestmt = $mysqli->prepare("SELECT picture FROM members WHERE username = ?");
        $picturestmt->bind_param('s', $postby);
        $picturestmt->execute();
        $picturestmt->bind_result($picture);
                        while($picturestmt->fetch()){
                                if(empty($picture)){
                                        $profpicturefromdb = " <img src='profile_pictures/public_icon.png' width='25' height='25' class='fxdmimg'>";
                                } else {
                                        $profpicturefromdb = " <img width='25' class='fxdmimg' height='25' src='profile_pictures/".$picture."' alt='Profile Picture'>";
                                }
                        }


echo 
"<p><center><div class='postdv'> 
<b>".$profpicturefromdb." 
<a href='http://www.fregbind.16mb.com/".$postby.".php'><h3>".$postby."</h3></a></b><font color='#000'>  
[ ".$posttime." ] </font>"; 
if($_SESSION['username'] == $postby){
     echo"<label for='pedform'><img src='pictures/ped.png' rel='icon' width='15' height='15' class='icnimg'></label>
     <label for='xdelform'><img src='pictures/xdel.png' rel='icon' width='15' height='15' class='icnimg'></label>
     <div class='hidden'><form method='POST'><input id='pedform' type='submit'></form> 
     <form method='POST'><input type='submit' id='xdelform'></form></div>";
     } 
     echo "<hr class='hrgray'><br>
<font color='#000'>".$posttxt."</font><p>";

$votestmt = $mysqli->prepare("SELECT upvotes, downvotes FROM posts WHERE id = ?");
$votestmt->bind_param('i',$postid);
$votestmt->execute();
$votestmt->bind_result($upvotes,$downvotes);
$votestmt->store_result();
while($votestmt->fetch()){

if(isset($_POST['voteup'])){
    echo $postid;
$onevalue = "1";
$makeitplusone = $upvotes + $onevalue;

$addvote = $mysqli->prepare("UPDATE posts SET upvotes = ? WHERE id = ?");
$addvote->bind_param('si',$makeitplusone,$postid);
$addvote->execute();

}
echo"<form method='POST'><input type='submit' name='voteup' class='voteup' value='Up'><font color='#00CC00'> ".$upvotes." </font>
    <input type='submit' name='votedown' class='votedown' value='Down'> <font color='#FF4747'>".$downvotes." </font>
    </form>
    </center>
    </div>";
}
}

?>

这里的代码略有不同。没什么不同，但这只需要在单击时将 upvote 的值更改为 +1，但是它将所有行更新为 +1...

编辑 3

我们正在谈论这部分：

$votestmt = $mysqli->prepare("SELECT upvotes, downvotes FROM posts WHERE id = ?");
$votestmt->bind_param('i',$postid);
$votestmt->execute();
$votestmt->bind_result($upvotes,$downvotes);
$votestmt->store_result();
while($votestmt->fetch()){

if(isset($_POST['voteup'])){
    echo $postid;
$onevalue = "1";
$makeitplusone = $upvotes + $onevalue;

$addvote = $mysqli->prepare("UPDATE posts SET upvotes = ? WHERE id = ?");
$addvote->bind_param('si',$makeitplusone,$postid);
$addvote->execute();

}
echo"<form method='POST'><input type='submit' name='voteup' class='voteup' value='Up'><font color='#00CC00'> ".$upvotes." </font>
    <input type='submit' name='votedown' class='votedown' value='Down'> <font color='#FF4747'>".$downvotes." </font>
    </form>

Answer 1

我不确定这段代码到底在做什么，但试试这个（第 38 和 49 行是修改）...

<?php
$selectposts = "SELECT postby,posttxt,time,upvotes,downvotes,id FROM posts ORDER BY id DESC";
$stmt = $mysqli->prepare($selectposts);
$stmt->execute();
$stmt->bind_result($postby,$posttxt,$posttime,$upvotesdb,$downvotesdb,$postid);
$stmt->store_result();
while($stmt->fetch()){
    $picturestmt = $mysqli->prepare("SELECT picture FROM members WHERE username = ?");
    $picturestmt->bind_param('s', $postby);
    $picturestmt->execute();
    $picturestmt->bind_result($picture);
    while($picturestmt->fetch()){
        if(empty($picture)){
            $profpicturefromdb = " <img src='profile_pictures/public_icon.png' width='25' height='25' class='fxdmimg'>";
        } else {
            $profpicturefromdb = " <img width='25' class='fxdmimg' height='25' src='profile_pictures/".$picture."' alt='Profile Picture'>";
        }
    }
    echo 
    "<p><center><div class='postdv'> 
    <b>".$profpicturefromdb." 
    <a href='http://www.fregbind.16mb.com/".$postby.".php'><h3>".$postby."</h3></a></b><font color='#000'>  
    [ ".$posttime." ] </font>"; 
    if($_SESSION['username'] == $postby){
        echo"<label for='pedform'><img src='pictures/ped.png' rel='icon' width='15' height='15' class='icnimg'></label>
        <label for='xdelform'><img src='pictures/xdel.png' rel='icon' width='15' height='15' class='icnimg'></label>
        <div class='hidden'><form method='POST'><input id='pedform' type='submit'></form> 
        <form method='POST'><input type='submit' id='xdelform'></form></div>";
        } 
        echo "<hr class='hrgray'><br>
    <font color='#000'>".$posttxt."</font><p>";
        if($_POST['upvoteid'] == $postid && isset($_POST['voteup'])){
            echo 'This:' . $_POST['upvoteid'] . ':equals:' . $postid . '.';
            $addvote = $mysqli->prepare("UPDATE posts SET upvotes = upvotes + 1 WHERE id = ?");
            $addvote->bind_param('i',$postid);
            $addvote->execute();
        }
        echo"<form method='POST'>
                <input type='submit' name='voteup' class='voteup' value='Up'><font color='#00CC00'> ".$upvotes." </font>
                    <input type='submit' name='votedown' class='votedown' value='Down'> <font color='#FF4747'>".$downvotes." </font>
                <input name='upvoteid' type='hidden' value='$postid'>
                </form>
                </center>
            </div>";
    }
}
?>

这样您就可以只运行更新已提交的更新。之前您正在检查是否设置了一个字段，该字段将为这些记录中的每一个设置。

如何只删除分配给该值的行？ （不知道标题怎么写）

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如何只删除分配给该值的行？（不知道标题怎么写）