如何从php中的SQL查询中获取一个值？

Question

如何使用php获取此查询的第一个结果？我想要列表按降序返回的第一个结果。

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

谢谢！

Answer 1

只需添加LIMIT 1到您的SQL结束

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'] . "'"; 

如果的customerID是一个数字，则单引号可以拆下来查询：

$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;