php - 减去 2 列并回显仅高于零的行

Question

正如主题所述，我对此有疑问。假设我有一个包含 3 列的表格。

materials | total amount | amount
==================================
mouse     | 5            | 2
keyboard  | 10           | 5
phone     | 5            | 5 

我用这段代码显示了这张表。

$result = mysqli_query($con,"SELECT * FROM materials");
while($row = mysqli_fetch_array($result))
  {
  echo  $row['materials'] 
  echo  $row['total_amount']
}

现在我想像这样显示这个表。

materials | total amount 
========================
mouse     | 3           
keyboard  | 5

如何存档，请指导我。

Answer 1

从总金额中减去金额

SELECT *
FROM tableName
WHERE `total amount` - amount > 0