Question

我的代码有问题，我已经从数据库中选择了浮点值，现在我想减去该值并将更新后的值更新到数据库表中在我的代码下方。

$AmountGiven = $_POST['AmountGiven'];
$conn = mysqli_connect("localhost","root","","xxx");


$selectuser = "SELECT * FROM users where email='$email'";
if($resultuser = mysqli_query($conn, $selectuser)){
    if(mysqli_num_rows($resultuser) > 0){
        while($row = mysqli_fetch_array($resultuser)) {
            $uuser_id = $row['uid'];
            $selctAllAmounttoShow = "SELECT * FROM donate WHERE user_id = '$uuser_id'";
            if( $resultToShowAmount = mysqli_query($conn, $selctAllAmounttoShow)){
                if( mysqli_num_rows($resultToShowAmount) > 0 ){
                    while($row = mysqli_fetch_array($resultToShowAmount)) {
                        $AmountAllToShow = $row['amount']; // these are float values
                    }
                }
            }
        }
    } else {
        echo "Login First";
    }
}
$updateAmount = "UPDATE donate SET amount = '$AmountAllToShow' - '$AmountGiven' WHERE user_id = '$uuser_id'";
$queryUpdateAmount = mysqli_query($conn,$updateAmount);
if($queryUpdateAmount){
    echo "ALL DONE";
} else {
    echo "ERROR";
}

$ AmountAllToShow此变量具有两个浮点值，例如0.5、0.7、0.3、0.6 = 2.1。

如果我所有行都有2.1值，那么我如何用1减去这些值，例如2.1-1 = 1.1，然后将此1.1值发送到$ row ['amount']和$ row ['amount']值0.3、0.7、0.1是发送到1.1之间的数据库编号的什么？

请帮助某人，谢谢StackOverFlow。

Answer 1

尝试

<div class="wrapper">
  <div class="item" id="item"></div>
  <div class="item1" id="item1"></div>
  <div class="item2" id="item2"></div>
  <div class="item3" id="item3"></div>
</div>

PHP-减去数据库选择的浮点值

1 个答案: