Question

我在使用简单的if语句在PHP while循环中工作时遇到了问题。这是我的代码：

$p=mysql_query("SELECT * FROM forum_posts WHERE forum_id='$cid' AND topic_id='$id' AND post_deleted='0' ORDER BY post_time ASC LIMIT  $offset, $rowsperpage");

while($post=mysql_fetch_assoc($p)){ 
    $userpost=$user->getUserData($post['userid']);

          if($userpost['specialmembership'] == 1){
            $pioneer = "True";
          }
echo $userpost['username'];
echo $pioneer;

}

因此，在上面的示例中，我有两个不同的用户。它们的名称为user1和user2。

User1有specialmembership = 0
User2有specialmembership = 1

上面的代码将输出以下内容（此示例中的while循环正在循环 4次）：

将输出：

user1

user2
true

user1
true

user2
true

问题在于，脚本在第三个循环中的user1上打印出true。 User1不应该设置为true，只有user2应该这样，因为他有specialmembership = 1;

这里有什么问题？

Answer 1

您应该添加else

if($userpost['specialmembership'] == 1){
      $pioneer = "True";
}else {
     $pioneer = "False";
}

因为一旦设置$pioneer的值不会改变（如果你不再这样做）

Answer 2

在设置为true后，您永远不会重置$pioneer，因此在第一个'true'用户之后的所有用户也将为true。你还需要一个：

      if($userpost['specialmembership'] == 1){
        $pioneer = "True";
      } else {
        $pioneer = "False";  // <---you need this
      }

Answer 3

尝试以下

$p=mysql_query("SELECT * FROM forum_posts WHERE forum_id='$cid' AND topic_id='$id' AND post_deleted='0' ORDER BY post_time ASC LIMIT  $offset, $rowsperpage");

while($post=mysql_fetch_assoc($p)){ 
    $userpost=$user->getUserData($post['userid']);

            $pioneer = "False";
          if($userpost['specialmembership'] == 1){
            $pioneer = "True";
          }
    echo $userpost['username'];
    echo $pioneer;
}

Answer 4

正如andrewsi所说，每次进入循环时都应该重置$pioneer变量。

while($post=mysql_fetch_assoc($p)){ 
  // defaults to 'False'
  $pioneer = 'False';
}

另一个选择是引入一个else分支：

else {
  $pioneer = 'False';
}

此外，您应 NOT 再使用已弃用的MySQL扩展程序！切换到MySQLi（带有准备好的语句）或PDO！

Answer 5

每次循环后你都没有重置$pioneer的值。如果它不应该是"true"，则将其重置为空字符串。

while($post=mysql_fetch_assoc($p)){ 
    $userpost=$user->getUserData($post['userid']);
        if($userpost['specialmembership'] == 1){
            $pioneer = "true";
        }else{
            $pioneer = "";
    echo $userpost['username'];
    echo $pioneer;
}

Answer 6

写

$p=mysql_query("SELECT * FROM forum_posts WHERE forum_id='$cid' AND topic_id='$id'      

AND post_deleted='0' ORDER BY post_time ASC LIMIT  $offset, $rowsperpage");

while($post=mysql_fetch_assoc($p)){ 
$userpost=$user->getUserData($post['userid']);
      $pioneer="False";
      if($userpost['specialmembership'] == 1){
        $pioneer = "True";
      }
echo $userpost['username'];
echo $pioneer;

}

Answer 7

您永远不会重置$Pioneer变量

尝试

$pioneer = $userpost['specialmembership'] == 1 ? "True" : "False or Whatever you want";

Answer 8

尝试添加其他条件，如

while($post=mysql_fetch_assoc($p)){ 
    $userpost=$user->getUserData($post['userid']);
          $pioneer = ($userpost['specialmembership'] == 1? "True": "False");
echo $userpost['username'];
echo $pioneer;
}

或在开头定义$ pioneer =“False”并使用您的代码

while($post=mysql_fetch_assoc($p)){ 
$userpost=$user->getUserData($post['userid']);

      if($userpost['specialmembership'] == 1){
        $pioneer = "True";
      }
echo $userpost['username'];
echo $pioneer;

}

php - if while循环中的语句

8 个答案: