Question

我正在开发一个离线聊天应用程序，我有两个表1.用户详细信息（cli_id，电子邮件，用户名）2。聊天表（c_from，c_to，subject，matter，image）现在的问题是我我从用户表中获取cli_id作为from和to，但是在获取查询时它返回一行，我的代码看起来像这样

<table width="100%" border="0">
  <tr>
    <td width="16%"><strong>From</strong></td>
    <td width="23%"><strong>Subject</strong></td>
    <td width="40%"><strong>Matter</strong></td>
    <td width="21%"><strong>To</strong></td>
  </tr>
  <?php
    include('connect.php');
    $sql=mysql_query("SELECT * FROM `chat` ORDER BY chat_id DESC")or die(mysql_error());
  while($row=mysql_fetch_array($sql))
  {
   ?>
  <tr>
    <td><?php echo $row['c_from']; ?></td>
    <td><a href="read_chat.php?id=<?php echo $row['chat_id']; ?>"><?php echo $row['subject']; ?></a></td>
    <td><a href="read_chat.php?id=<?php echo $row['chat_id']; ?>"><?php echo $row['matter']; ?></a></td>
    <td><?php
$chat_to =$row['c_to'];
    $sql=mysql_query("SELECT * FROM `client` WHERE cli_id = $chat_to")or die(mysql_error());
  while($qry=mysql_fetch_array($sql))
  {
  echo $qry['email'];
  }
   ?></td>
  </tr>

  <?php } ?>
    </table>

Answer 1

你在循环中覆盖$sql，它用一个结果集替换外循环中的结果集，该结果集在代码执行返回外循环时已经被“清空”。

Answer 2

$ sql变量在while循环中发生了变化。在这里使用不同的变量：

$sql=mysql_query("SELECT * FROM `client` WHERE cli_id = $chat_to")or die(mysql_error());

Answer 3

试试这个：

<table width="100%" border="0">
  <tr>
    <td width="16%"><strong>From</strong></td>
    <td width="23%"><strong>Subject</strong></td>
    <td width="40%"><strong>Matter</strong></td>
    <td width="21%"><strong>To</strong></td>
  </tr>
  <?php
    include('connect.php');
    $selectChat=mysql_query("SELECT * FROM `chat` ORDER BY chat_id DESC")or die(mysql_error());
  while($row=mysql_fetch_array($selectChat))
  {
   ?>
  <tr>
    <td><?php echo $row['c_from']; ?></td>
    <td><a href="read_chat.php?id=<?php echo $row['chat_id']; ?>"><?php echo $row['subject']; ?></a></td>
    <td><a href="read_chat.php?id=<?php echo $row['chat_id']; ?>"><?php echo $row['matter']; ?></a></td>
    <td><?php
$chat_to =$row['c_to'];
    $selectClient=mysql_query("SELECT * FROM `client` WHERE cli_id = $chat_to")or die(mysql_error());
  while($qry=mysql_fetch_array($selectClient))
  {
  echo $qry['email'];
  }
   ?></td>
  </tr>

  <?php } ?>
    </table>

Answer 4

为了最大限度地减少数据库请求的数量，最好使用连接，这样也可以减少在第一个循环中有第二个查询循环的需要。请尝试以下代码

<table width="100%" border="0">
<tr>
<td width="16%"><strong>From</strong></td>
<td width="23%"><strong>Subject</strong></td>
<td width="40%"><strong>Matter</strong></td>
<td width="21%"><strong>To</strong></td>
</tr>
<?php
include('connect.php');
$sql=mysql_query("SELECT * FROM `chat` LEFT JOIN 'client' on 'chat.c_to = client.cli_id' ORDER BY chat_id DESC")or die(mysql_error());
while($row=mysql_fetch_array($sql))
{
?>
<tr>
<td><?php echo $row['c_from']; ?></td>
<td><a href="read_chat.php?id=<?php echo $row['chat_id']; ?>"><?php echo $row['subject']; ?></a>  </td>
<td><a href="read_chat.php?id=<?php echo $row['chat_id']; ?>"><?php echo $row['matter']; ?></a></td>
<td><?php echo $row['email'];?></td>
</tr>

<?php } ?>
</table>

Answer 5

您必须重写主查询后立即出现的while语句

while($row=mysql_fetch_array($sql))

as

while($row=mysql_fetch_row($sql))

希望这对你有所帮助。

php查询返回单行的内容

5 个答案: