PHP没有在多个条件下回显sqli查询

Question

我正在尝试回显查询结果。当我在phpmyadmin SQL框中运行查询时，它返回正确的信息。当我将其添加到php中时，如果添加第二个条件（如AND

），它不会回显任何内容

不返回任何内容

 $query = "SELECT * FROM CwAp_postmeta WHERE meta_key = 'adurl' AND post_id = '31'";
 mysqli_query($db, $query) or die('Error querying database.');


 $result = mysqli_query($db, $query);
 $row = mysqli_fetch_array($result);

 while ($row = mysqli_fetch_array($result)) {
  echo $row['meta_value'];
 }

会退货吗

 $query = "SELECT * FROM CwAp_postmeta WHERE meta_key = 'adurl'";
 mysqli_query($db, $query) or die('Error querying database.');


 $result = mysqli_query($db, $query);
 $row = mysqli_fetch_array($result);

 while ($row = mysqli_fetch_array($result)) {
  echo $row['meta_value'];
 }