检查数据库中的表是否为空

Question

我有一个称为请求的表，我想检查该表是否为空。如果是，我只想输出一条语句。我尝试使用mysqli_num_rows，但是它不起作用。谢谢

  <?php

     $servername = "localhost";
     $username = "root";
     $password = "";
     $dbname = "project";

     $conn =  new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

mysqli_select_db($conn, 'project');

$sql = "SELECT count(*) FROM requests ";
$records = mysqli_query($conn, $sql);
$ifempty = mysqli_num_rows($records);


while($row = mysqli_fetch_array($records)){
    if($ifempty > 0)){
     echo "<tr>";
     echo "<td>".$row['LastName']."</td>";
     echo "<td>".$row['FirstName']."</td>";
     echo "<td>".$row['email']."</td>";
     echo '<td><a href=accept.php?id=' .$row['Emp_ID'].' data-toggle = "modal" class= "btn btn-success"><span
     class="glyphicon glyphicon-ok"></span> Accept</a></td>';

     echo '<td><a href=reject.php?id=' .$row['Emp_ID'].'data-toggle = "modal" class= "btn btn-danger"><span
     class="glyphicon glyphicon-remove"></span> Reject</a></td>';
     echo "</tr>";
   }
   else {
    echo "no pending requests";
   }




}

?>