php - 根据选择mysql php更新总价

Question

你好我希望有人能帮助我。我需要知道如何编写查询，以便根据燃料数量选择添加一个值。

例如，假设用户选择 100 升，然后将 £5 添加到总计中，或者如果他们选择 500 升，则添加 £15 等。

这是我目前用于计算每升价格的代码。

// show price
        $fuelPriceQuery = sprintf("SELECT `Price` FROM fuel_price WHERE FuelType = '%s' LIMIT 1",
                    mysql_real_escape_string($_POST['fueltype']));

        $fuelPriceResult = mysql_query($fuelPriceQuery);
        $price           = mysql_fetch_array($fuelPriceResult, MYSQLI_ASSOC);

        echo 'The Price Today is £'.($_POST['qtylitres'] * $price['Price']);
        echo "<br />";
        echo "For " . ($_POST['qtylitres']) . " Litres of " .($_POST['fueltype']);

echo "<br />" . "<br />";

if(mysql_num_rows(mysql_query("SELECT * FROM subscribe WHERE Email = '".mysql_real_escape_string($_POST['inputEmail'])."'")))
{
     echo "Thanks but we already have your email";
}   
else
{

Answer 1

通过这段代码扩展您的代码，如果我理解正确的话，它应该完全按照您的要求执行。

[...]
if($_POST['qtylitres'] >= 100)
  $fee = 5;
if($_POST['qtylitres'] >= 500)
  $fee = 15;

echo 'The Price Today is £'.(($_POST['qtylitres'] * $price['Price'])+$fee);
[...]