如何从 php 中的 SQL 查询中获取一个值？

Question

如何使用 php 获得此查询的第一个结果？ 我想要列表按降序排列时返回的第一个结果。

$sql2 = "SELECT orderID FROM orders WHERE 'customerID' = '".$_SESSION['accountID']."' ORDER BY
                    'orderID' DESC";
                $lastorder = mysqli_query($sql2);

谢谢！

Answer 1

只需将LIMIT 1添加到 SQL 的末尾

Answer 2

使用LIMIT ：

'SELECT orderID FROM orders WHERE customerID = "' . $_SESSION['accountID'] . '" ORDER BY orderID DESC LIMIT 1'

Answer 3

查询：

$query = "SELECT MAX(orderID) as orderID
            FROM orders 
            WHERE customerID = '" . $_SESSION['accountID'] . "'";

如果 customerID 是数字，则可以删除单引号以进行查询：

$query = "SELECT MAX(orderID) as orderID
            FROM orders 
            WHERE customerID = " . $_SESSION['accountID'];

然后...

// include database_link since you are not using OO-style call.
$result = mysqli_query($database_link, $query); 
$row = $result->fetch_object();
$orderID = $row->orderID;