PHP -尝试对从数据库检索的数据使用上限函数时出错

Question

下面是我的PHP代码。我将从数据库中检索值，并将其舍入最近的10 (仅在10以上)。本列中数据库中的所有值都是整数。

<?PHP
    @$Teach_ID = $_POST['txtteachID'];
    @$Class_ID = $_POST['txtclass'];
    @$BookingDate = $_POST['txtbookingdate'];
    @$BookingPeriod = $_POST['txtperiod'];

    require_once('../BookingSystem/DBconnect.php');

    $capacity = 'SELECT ClassSize FROM classes WHERE ClassID = 1';
        $result = $dbh->query($capacity);
        $result = (int)$result;
    function ceiling($number, $significance = 1)
        {
            return ( is_numeric($number) && is_numeric($significance) ) ? (ceil($number/$significance)*$significance) : false;
        }
    }

    if ($result->num_rows > 0) {
        echo ceiling($result, 10);
    }
    ?>

错误描述

​

​

我漏掉了什么明显的东西吗？

Answer 1

您需要循环遍历$result变量，这是一个mysqli_result对象，以获得它的不同条目。

使用mysqli_fetch_assoc获取值，其结尾如下所示：

$capacity = 'SELECT ClassSize FROM classes WHERE ClassID = 1';
$result = $dbh->query($capacity);
function ceiling($number, $significance = 1)
{
    return ( is_numeric($number) && is_numeric($significance) ) ? (ceil($number/$significance)*$significance) : false;
    }
}

while ($row = $result->fetch_assoc()) {
    // if ($result->num_rows > 0) { /* I think this condition is not needed anymore */
        $value = intval($row['ClassSize'], 10); // will convert the string from database to an int in base 10
        echo ceiling($value, 10); /* I suppose you wanted to use the ClassSize key since it's the one you query */
    // }
}

Answer 2

你不能做这个$result = (int)$result;。你必须激怒每一行，然后提取数据。