Question

<?php
 function comment($postid,$db_con)
{
 $commentdiv='';
 $sql="SELECT userid,time,comment FROM comments WHERE postid='$postid' LIMIT 3";
 $query = mysqli_query($db_con, $sql); 
while($row = mysqli_fetch_array($query,MYSQLI_ASSOC)){
    $uid=$row["userid"];
    $timecomment=$row["time"];
    $comment=$row["comment"];
$sql="SELECT username,photo FROM users WHERE id='$uid'";
$query = mysqli_query($db_conx, $sql); 
$row = mysqli_fetch_array($query,MYSQLI_ASSOC);
 $username=$row["username"];
 $photo=$row["photo"];
 $userphoto='<img src="xxx/'.$username.'/'.$photo.'">';
 if($photo== NULL){
     $userphoto = '<img src="xxx/default.png">';
 }
 $commentdiv.='<div class="xxxxxxx"><div class="yyyyyy">'.$userphoto.'</div><div class="zzzzz">'.$username.'</div><div class="vvvvv">'.$comment.'</div></div>';
}
return $commentdiv;
}
?>

我是PHP的新手，我试图从上面的PHP代码返回3条评论，但上面的代码只返回数据库中的1行，为什么当有多于1行时，fetch数组只返回1行？

Answer 1

您正在覆盖在while循环中提供结果的mysql资源变量。

while($row = mysqli_fetch_array($query,MYSQLI_ASSOC)){
                                ^^^^^^ Original resource variable

再次在while循环内部使用查询变量

$query = mysqli_query($db_conx, $sql); 
^^^^^^ Overwriting $query inside the while loop

一个建议是将循环中的变量重命名为其他内容。

Answer 2

尝试，我使用$query2 = mysqli_query($db_conx, $sql);进行第二次查询，因为它会重置第一个循环

 <?php
 function comment($postid,$db_con)
 {
 $commentdiv='';
 $sql="SELECT userid,time,comment FROM comments WHERE postid='$postid' LIMIT 3";
 $query = mysqli_query($db_con, $sql); 
  while($row = mysqli_fetch_array($query,MYSQLI_ASSOC)){
  $uid=$row["userid"];
  $timecomment=$row["time"];
  $comment=$row["comment"];
  $sql="SELECT username,photo FROM users WHERE id='$uid'";
  $query2 = mysqli_query($db_conx, $sql);  // added new variable
  $row = mysqli_fetch_array($query2,MYSQLI_ASSOC);
  $username=$row["username"];
  $photo=$row["photo"];
  $userphoto='<img src="xxx/'.$username.'/'.$photo.'">';
 if($photo== NULL){
    $userphoto = '<img src="xxx/default.png">';
  }
     $commentdiv.='<div class="xxxxxxx"><div class="yyyyyy">'.$userphoto.'</div><div         class="zzzzz">'.$username.'</div><div class="vvvvv">'.$comment.'</div></div>';
 }
 return $commentdiv;
}
?>

获取数组只返回一行

2 个答案: