php - 列的 SUM 不起作用，它只打印 0

Question

<?php
  $con=mysqli_connect("localhost","root","root","test");
  // Check connection
  if (mysqli_connect_errno())
  {
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

  $results = mysqli_query($con,"SELECT SUM(jumlah) AS jumlah_sum FROM finance_income"); 
  echo '<center>';

 /*while($rows = mysqli_fetch_array($results)); 
 { *?
     echo "<p>" . "Rp " . number_format($rows['jumlah_sum']) . "</p>";
 /*}*/
 echo "</center>";

 mysqli_close($con);

?>

那是我的代码，我认为它正在工作，但是当我在我的 mamp 中打开它时，它只打印了 0 而不是 2,800,000，2,800,000 是列“jumlah”的总和

id timestamp_ _ __ _ __ _ nama cat_id jumlah

1 2013-10-26 14:08:18 测试 Iuran 400000

2 2013-10-26 22:06:35 测试多纳西 2000000

3 2013-10-27 10:51:32 测试 Iuran 100000

4 2013-10-27 10:55:01 测试 Iuran 100000

5 2013-10-27 11:01:38 测试 Iuran 100000

6 2013-10-27 11:02:07 测试 Iuran 100000

编辑：我尝试删除 while 并且它有效，谢谢

Answer 1

这是工作代码。

<?php
  $con=mysqli_connect("localhost","root","root","test");
  // Check connection
  if (mysqli_connect_errno())
  {
     echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }

  $results = mysqli_query($con,"SELECT SUM(jumlah) AS jumlah_sum FROM finance_income"); 
  echo '<center>';
  $rows = mysqli_fetch_array($results);
  echo "<p>" . "Rp " . number_format($rows['jumlah_sum']) . "</p>";
  echo "</center>";
     mysqli_close($con);

    ?>